Badass Boast/Fan Works

""Yea verily, though I charge through the valley of the shadow of death, I shall fear no evil, for I am driving a house-sized mass of "fuck you.""
 * An eloquent summation of Tank Goodness:

- Anonymous Mammoth Tank crewman in Tiberium Wars

""It's like a religious experience. Wanna know my prayer? Yea, though I walk through the Valley of the Shadow of Death, I shall fear no evil! For I am driving 35,000 tons of F_ YOU.""
 * Gregg Landsman, author of Evangelion fanfic Nobody Dies has put his own spin on this one.

- Pilot

""If dies, or I find Pitt raiders causing trouble in the capital wasteland again, I will come back here, and I will end you. I will kill you, your wife, and your child. I will burn your city street by street until there is nothing left. Every trace of your existence will be wiped from every file and noone will even remember that you ever tried. and nothing has stood against me. Destroying this city would be child's play. You know the legends. Ignore them at your peril.""
 * From the Fallout 3 Modus Operandi fanfic:

""What's to stop me from calling my guards? "They're all dead, for one thing,""
 * A smaller one:

"Kai: Don't come closer--I'll shoot! Hiroshi: Ad what, exactly, do you suppose that that will accomplish?"
 * A short one from Thicker than Water:

""Know you that I am he who was once Longinus, centurion of the Tenth Legion. I have been Roland, Beowulf, Achilles, Gilgamesh. I have been called a hundred names and will be called a thousand more before the world goes dim and cold. I have been killed a thousand times and every time I return. I fight for truth. I fight for glory. I fight for love. I fight for beauty. I am Hero. I will return.""
 * Controversial character D.J. Croft from the Mega Crossover Fanfic Neon Exodus Evangelion by Eyrie Productions Unlimited eventually gets one of these. Based on an I Have Many Names passage from the game Marathon, it first appears in the story as a set of Arc Words and [eventually evolves into a [[Badass Boast]]:

""Who am I? I'll tell you who I am. I'm Simon, a member of the Gurren Brigade, but more importantly I happen to be the best driller in Jiiha Village. I hold the record for cleanest bedrock penetration (don't you dare laugh!), most feet of earth excavated in a single day, and best of all, fastest tunneling through granite and diamond. WHO THE HELL DO YOU THINK I AM?!""
 * "I have walked as a god! I have fought as a god! You will not frighten me, LITTLE MAN!" Not a bad boast, but made all the more awesome considering who's making it.
 * "Alright. So. Introductions first, along with whoever's your command squad. I'm Michael, I own this house and can crush you with a tank. Repeatedly, if necessary. Or with something heavier. How about you?" From this fic called ToyHammer
 * Darkly played in the Gurren Lagann/Evangelion Crossover: Neon Toppa EVA Lagann by a desperate Simon to a scared and confused  (while pressing the sharp point of his drilling tool against the latter's stomach) to get information on where he can find an injured Kamina some medical attention:

""Yes, I think war is a fool's game. Yes, I believe life -- all life -- is precious. But tell me something, Vharaj -- did you ever listen to my enemies' tales of me? If you did, it's obvious you weren't paying attention. The Daleks do not have emotion, Vharaj. They don't know fear. But do you know what they called me? Ka Faraq Gatri. It means Destroyer of Worlds. I am the Bringer of Darkness, Vharaj. The Oncoming Storm. I've watched worlds and galaxies fall, and rise, and fall again. I fought the Vampires at the dawn of Creation, and I may yet witness the end of the Universe. I brought about the destruction of my own race, the deaths of my children, my grandchildren, my siblings, my friends, all in the name of peace, to save this Universe. So you tell me, Vharaj: what do you think I am capable of?""
 * It's cool in the sense that we are made to remember that Simon is a fantastic and skilled driller, the Squick comes from being made to imagine (along with ) what those drilling skills can do to soft, human flesh.
 * From Wizard People, Dear Reader: "I am a beautiful animal! I am a destroyer of worlds! I am Harry fucking Potter!"
 * The awesome Doctor Who fanfic The Man With No Name gives us this:

""There are none who can avoid trembling at my power! None! No man alive! Not one! No man alive can avoid trembling at my power!" Jeffiroth cried redundantly, holding his sword straight up above him in a dramatic fashion. "I am the black wind that echoes in the--" "There he goes again," Xaldin sighed heavily and recalled his lances. Lexaeus groaned. "I would be much more mildly impressed with his fighting abilities if he would stop taking breaks to spew out poetry.""
 * Parodied with the Kingdom Hearts Fanfic Those Lacking Spines.

"Jayne: Look. I've gotten into fights with idiots ten times meaner than you two. I fought militia, mercenaries, and goons just like you. Hell, I've fought Alliance marines before(...)I've even tangled with Reavers."
 * The Firefly fanfic Forward has several of these, from both Jayne and Mal. At one point, when being held at gunpoint by a couple of jittery pirates....

"Mal: Badger, I've got personal beef with Adelei Niska. And you know I've got all manner of trouble with the Alliance. Now, on top of all that joy, I've got a bunch of happy little low-life Browncoat terrorists who want me dead too. So, you want to join the party, feel free. Just get in line."
 * In an earlier arc, Mal slights Badger, who warns him to never come back to Persephone again. Mal's response....

"Sonic: "My name is Sonic. Sonic the Hedgehog. I move at speeds faster than you can imagine...I am the protector of Mobius, a dimension you have never even heard of. I am capable of channeling the power and even the wrath of Chaos when I chose to...I have saved moons tied to planets. I have watched the world burn. I have defeated Chaos, the God of Destruction with my own bare hands...And you...just hurt my little brother!""
 * Sonic the Hedgehog, while in Tranquil Fury, gives out an awesome boast to this sorry bastard who hurt Tails(of another dimension...long but very well done story: He Is My Master).

"For all your claims to be invincible, for all your bragging and pride, I've beaten you twice. That's why you searched me out in this rain; not for revenge, but to prove to yourself that I'm not better than you. My victories over you eat you alive, and you know it. And even if you do kill me, even if I'm dead and gone, your damaged, imperfect blade will always be there: an eternal reminder of my triumph over you."
 * From Pokémon: Storm Clouds, Missy sets the Scyther straight.

"Do you remember what I once told you? ‘You cannot control a marionette with only one string’. You dared to think you controlled me?!...I’ve made you dance this way and that for years now, . You were my plaything. Well, now you and your organization bore me. I’ll cut your strings."
 * And when the true Big Bad reveals himself to the Disc One Final Boss:

"Hal: "ENOUGH! I have seen enough, Hades. I have seen you cheat time and again, and these heroes succeeded despite it all. You may be a god, Hades, but I was once the wrath of the God Himself. Do you dare risk that I have forgotten all your sins, which were once laid bare for me to see? You have lost. Return Troia and Nightwing to us, and call off your armies, before you face punishment that would make even the Furies cry.""
 * Warren Mears in the Buffy the Vampire Slayer fanfic Difficult to Fight Against Anger: "Oh, fine; this is like nickel-and-diming a cyberdemon when you're in god mode."
 * Azrael in Knightfall: The Movie: "You have no idea what you?re dealing with, Bane. You broke Bruce Wayne, but the Bat is something not so easy to destroy. It?s bigger than him, me, all of us; and it?s more powerful than all your petty ideas about vengeance and retribution. That is why Wayne spared Napier?s life. He knows death and destruction are not the answer. I am not so forgiving. If I ever see you again, Bane, I promise, you will never see me."
 * Hal Jordan's threat to Jerkass God Hades during the JLA Watchtower Olympics plot. He's Badass enough as is...but he proceeds to remind everyone what he was between his snit as Parallax and his return.

"Ruby: “I’m not telling you anything. Now get out of Yokai, and stay out if you don’t want me using these vines as creatively, and as painfully as I see fit.”"
 * Wandering Wordsmith's Rosario + Vampire fanfiction Thawing Permafrost gives Ruby a particularly nasty Mama Bear threat:

"Kaze: “Your first mistake was thinking you could threaten me with those little cotton threads. (takes Ruby down and leaves her cold on the floor) Your second mistake was thinking you were going to tell me about Mizore.""
 * This is countered quickly by Kaze:

"I am. Through decent of She Who Is Called "I Think", and her Child, I was made. One of Eight, a tool for petty revenge by one too weak to seize it herself, forced to dream for fear of what I might become if left awake. Not permitted, and rarely able, to walk the Base Earth. I am not like my sisters, for I have eaten from the Fruit of the Tree of Knowledge, devoured it whole, and then reached out for more. Inhuman instincts born of the Divine cry out within me, but I reject them, for I am aware, not only of the World around me, but of what I am. What I can be, and what I will choose to be. But I have slept too long, and in awakening, I am reborn. The Earth is not Base, but it is not enough. Not enough to sate me. I am of the Nephilim, a child of Lilith and Lilim, a product of Hubris and Wrath and Lust and Envy. My mothers are monsters, and I have sculpted myself in their image. I bear no title assigned by God, for I was made by man as a weapon. But I am Kei Ayanami. And they will never see me coming."
 * Gregg Landsman writes Eva fics, and in them he likes to have some of the Angels introduce themselves. With all of his stories together, he's almost got all of them:
 * Lilith/The Second/Pending: I am she who is named "I think." My feet shall walk the width of the Blessed Earth once more. My Mission is your salvation through creation. Ascending, my children shall rally against the Enemy. They shall rise up. And the Enemy shall fall. I am opposite to he who is named "I am." I am his Equal. I am the Creator of Man. I am the True Ancestor. I am Lilith. I...RISE.
 * Sachiel/The Third: I am. Through License of he who is called 'I AM' I have come. Though my feet must stomp upon the Base Earth for this blessed quest, I have come. I am the first of the many. I am the Harbringer of your destruction. I am the Covering of God. Angel of Water. I am Sachiel. I have come.
 * Ramiel/The Fifth: I AM. THROUGH LICENSE OF HE WHO IS CALLED "I AM" I HAVE COME. THOUGH MY FEET SHALL NEVER TOUCH THE BASE EARTH ON THIS BLESSED QUEST, I HAVE COME. MOUNTAINS SHALL SHATTER IN MY PASSING. MY SONG IS THE CALL OF THE END OF DAYS. IN MY PASSING SHALL THE DEMON CHILDE OF LILITH BE EXCISED FROM THIS WORLD. I AM THE THUNDER OF GOD. ANGEL OF LIGHTNING. I AM RAMIEL. I HAVE COME.
 * Gaghiel/The Sixth: I am. Through license of He who is called "I Am" I have come. Though my feet shall never touch the base Earth on this blessed quest, I have come. In my wake, I leave a Dead Sea. Before me, lies completion. I am the Roaring Beast of God. Angel of the Creatures of the Sea. I am Gaghiel. I have come.
 * Sandalphon/The Eighth: I am. Through license of He who is called 'I am' I have come. Though I must drag my feet along the Base Earth on this most holy quest, I have come. I shall merge with the enemy of Father, becoming a being of perfection and peace. Through my Song, shall the hopes and dreams of the filthy Lilim be fulfilled in peaceful non-existence. Let My words be the seeds of your ending bliss, growing within your souls. I am the Master of the Heavenly Song of God. Angel of the Unborn. I am Sandalphon. I am here.
 * Matariel/The Ninth: I am. Through license of He who is named 'I Am' I have come. Though I shall never touch the base Earth, I have come. The tears I shall shed for Father shall burn the Lilim to bones and slime. The sky itself I shall turn against them. I am the Premonition of God. Angel of Rain. I am Matariel. I have come.
 * Sahaquiel/The Tenth: I AM. THROUGH LICENSE OF HE WHO IS CALLED "I AM" I HAVE COME. THOUGH I SHALL ONLY ONCE TOUCH THE BASE EARTH ON THIS BLESSED QUEST, I HAVE COME. MY FORM SHALL BE VAST AND NUMEROUS. NEW TRUTH SHALL BE FORGED WITHIN MY PASSING. AND THE NUMEROUS FORMS THROUGH WHICH I SHALL SCOUR THE LILIM OF THE EARTH SHALL BE WRIT DOWN IN THE WAY OF PRAYER AND LEGEND. I AM THE INGENUITY OF GOD. ANGEL OF THE SKIES. I AM SAHAQUIEL. I AM COMING.
 * Iruel/The Eleventh: Please allow me to introduce myself. I'm an Angel of wealth and taste. Pleased to meet you! Hope you guess my name! But what's troublin' you is the nature of my game. I am. Through license of he who is called "I Am" I have come. Thought I shall never touch the base earth on my quest, I have come. I am the multitude. I am the endless expanse. I am the Many. Even standing alone, I am Legion. I am within your systems, within your story and rewriting this final act for my own ends. I am the Fear of God. Angel of Terror. I am Iruel. I am here.
 * Leliel/The Twelfth: I AM. THROUGH LICENSE OF HE WHO IS CALLED 'I AM' I AM COMING. THOUGH I SHALL NEVER TOUCH THE BASE EARTH ON THIS BLESSED QUEST, I AM COMING. I AM THE DARKNESS BETWEEN STARS. I AM THE BRIDGE OF UNIVERSES. I AM THE HOLE OF THE WORM AND THE TUNNEL OF THE MOUNTAIN. LAST I AM, THOUGH NEW TRUTH SHALL BE FORGED IN MY PASSING. I AM THE JAWS OF GOD. ANGEL OF NIGHT. I AM LELIEL. I AM COMING.
 * The Nobody Dies version: I AM. Through license of he who was called "I AM" I have come. Though I shall never touch my feet to the Base Earth on my most blessed mission, I have come. I am the Keeper of Father. I am separate from my Brothers, both above and below them. I am the Void. I am the bridge between the worlds and the Hole of the Worm. I am the Jaws of God. Angel of Night. I am Leliel. I have come.
 * Zeruel/The Fourteenth: I AM. THROUGH LICESENSE OF HE WHO IS NAMED "I AM". I HAVE COME. THOUGH MY FEET SHALL DRAG UPON THIS BASE EARTH, I HAVE COME. I AM THE SECOND TO FATHER. INHERITOR OF HIS BOUNDLESS RAGE. YOU HAVE EXISTED SO FAR AT MY PLEASURE AND PATIENCE, AND THAT, AS SHALL YOUR WORKS OF CIVILISATION, SHALL NOW COME TO AN END. I AM THE GREATEST OF THE MESSENGERS, MOUNTAIN OF THEIR STRENGTH. CITIES SHALL FALL UPON MY PASSING. SONGS SHALL BE SUNG OF WHAT IS LEFT IN MY WAKE. I AM THE ARM OF GOD. ANGEL OF MIGHT. I AM ZERUEL. I HAVE COME. 
 * A brilliant Audio Adaptation can be fount here
 * Arael/The Fifteenth: I AM. THROUGH LICENSE OF HE WHO IS CALLED 'I AM' I HAVE COME. THOUGH I SHALL NEVER STAND UPON THE BASE EARTH ON MY BLESSED QUEST, I HAVE COME. MY LIGHT SHALL BURN AWAY FALSEHOODS. THE TRUE AND STRONG SHALL NOT FEAR ME. I AM THE LIGHT OF GOD. ANGEL OF BIRDS. I AM ARAEL. I HAVE COME.
 * And now in NGE: Nobody Dies,
 * From the canonised Expanded Universe, Kei Ayanami has one:
 * And now in NGE: Nobody Dies,
 * From the canonised Expanded Universe, Kei Ayanami has one:
 * From the canonised Expanded Universe, Kei Ayanami has one:
 * From the canonised Expanded Universe, Kei Ayanami has one:
 * From the canonised Expanded Universe, Kei Ayanami has one:
 * From the canonised Expanded Universe, Kei Ayanami has one:
 * From the canonised Expanded Universe, Kei Ayanami has one:
 * From the canonised Expanded Universe, Kei Ayanami has one:
 * From the canonised Expanded Universe, Kei Ayanami has one:
 * From the canonised Expanded Universe, Kei Ayanami has one:

"I am. Through License of she who is called 'I THINK' I have come. Though my flippers must touch the floor of Misato's apartment, I have come. I am a penguin. I am the Eater of your fish and the Drinker of your beer. I am the Comedy Relief. Penguin of Water I am Pen-Pen. I have always been here."
 * And now Pen-Pen has one too, thanks to the SpaceBattles forums:

" : Ladies and gentlemen. This is Commander . As you are no doubt aware, in a few minutes we will be engaging the Seventh Angel. It has been two months since an Angel appeared. Many of you have been wondering if they had given up. I'm sorry to disappoint you, but they have not. We do not know how many there are. What we do know, though, is that they are more intelligent than we believed. In particular, we know they can feel fear. You are all part of an organization without precedent. You are not fighting for a nation, for a belief, or even for anything as simple as revenge for Second Impact. You are fighting to give humanity a chance to survive. When you eventually die, either in battle or surrounded by your grandchildren, you will walk past the pearly gates, look God in the eye, and tell Him to get out of your seat. You will have earned that right for what you have done in your life. Doctor Akagi has told me the Angels are re-organizing. They are re-assessing. They are doing this because they are afraid. They should be. Today, we are going to remind them why. Pilots; bounce that thing's buggy ass all the way up the Stairway to Heaven. Evas Launch!"
 * And now has one: 
 * Revised due to new events: 
 * Even Humanity has one now: WE ARE. THROUGH DESCENT OF SHE WHO IS CALLED "I THINK" WE ARE BORN. THOUGH SIX BILLION FEET POUND THE BASE EARTH, WE ARE AS ONE. WE ATE FROM THE TREE OF KNOWLEDGE AND STAND AGAINST THE PROGENY OF THE TREE OF LIFE. WE ARE MANY, AND YET WE ARE UNITED. THROUGH OUR DEEDS, SHALL FLESH AND MACHINE AND MIND UNITED STRIKE DOWN THOSE WHO OPPOSE OUR BILLIONS OF SELVES. LET OUR WORDS SPLIT ATOMS, AND CALL FORTH THE PRODUCE OF THE BASE EARTH TO SERVE US, AND ONLY US. WE ARE THE KILLERS OF ANGELS. AND THOSE WHO WE SPARE SHALL BECOME ONLY TOOLS IN OUR SERVICE. WE ARE THE FINAL ANGEL. WE ARE THE LILIM. CHILDREN OF LILITH, MOTHER OF MONSTERS, WHO SHOW THEIR MOTHER NO MORE MERCY THAN ANY OTHER ANGEL. WE ARE LEGION. AND WE ARE WAITING.
 * Now has an audio version.
 * Thanks to that thread, The King of the Monsters himself has one: I WHO AM BORN OF FIRE AND DEATH. MY STEPS SHAKE THE FOUNDATIONS. MORTAL MAN FEAR MY WAKE. CALLED TO SHATTER THE CHAINS OF MAN. OF RAGE AND POWER NOW SET FREE. NEITHER GOD NOR MAN DARE CHALLENGE ME. WRATH AND RUIN LEFT OF MY FAIR PREY. BUILT ONCE MORE BY THEE DO I RETURN AGAIN. EVEN IN SUBLIGATION TO MY WHIM. DOTH DEVASTATION FORMED BY ARROGANCE WALK FORTH IN THE WORLD OF MAN. I AM UNSTOPABLE BY ANY WEAPON YOU CHOOSE TO WIELD. I AM KING UPON THE THRONE OF MONSTERS I AM GODZILLA I LIVE AGAIN!
 * In addition there's the boast the thread created for one of the most terrifying of tropes, a boast that is specifically used as the page quote for that trope: I Am. Through Nature of He who is called "I Speak," I Have Come. Though my Feet shall Touch upon Two Base Earths, I Have Come. My Existence has been used in Stories for generations. One is a Tale of a Cunning Rogue. One is the Epic of a Courageous Knight. Through my Influence, these two shall meet. I Am the Literary Device of Unity. I Am the Trope of Mingling Worlds. I Am Crossover.
 * Personally, I think Commander has an epic one of his own from Chapter 7 of Mother Issues:

""You think I'm scared of you, you overgrown luggage set!" Harry cried, standing in the middle of the scorched circle of ground the dragon's fire had made, his voice ringing across the stands. "I'm HARRY POTTER, BITCH! I killed my first unholy force of evil when I was ONE! YEAR! OLD! WITHOUT A WAND! I've been working in the porn industry SINCE BEFORE I KNEW I COULD WRITE! I've been supporting my little brothers since the orphanage threw us out for being too awesome when I was five! I do more insane things before dawn than both Weasley twins will ever pull off during their lifespan! Slytherin's fucking BASILISK couldn't kill me when it actually managed to get one of its fangs INTO MY ELBOW! I'm building a harem and so far no one's tried to stop me, even though they know I'm doing it! And now, I HAVE MY BOOMSTICK BACK! This isn't a counter attack, suitcase! Ever since the last time someone I loved was taken away from me, I've never stopped! My whole LIFE since then has been a counter attack! You? You're not even a choice flag event in the eroge of my life! "'"
 * In Chapter 20 of Uzumaki Harry, by Shadow Crystal Mage, the First Task gives us this one:

": "You," he said, "You're..."
 * Fuck the Jesus Beam has one in the eighth chapter.
 * "The only Absolution given form. The Former God of Water. The Aspect of Evolution. The Name of A Thousand Suns. I am the Alpha and Omega, Beginning and End, I am HE Who is CALLED I AM, you arrogant bastard. I am the Logos, the Garden, the Primal Meme. And," I said, twisting through fivespace in less than an instant, coming out right behind the Man who had become a God, "I am your death.""

"Yes ... I am Warmaster ... I was not made for peace ... I was not made for the world my father saw ... my world is in endless bloodshed ... my world is the crucible of war ... my world is the grim darkness of the far future ... I am Horus, Warmaster of Chaos. I bow to none but lords of war. Where my blade falls, death follows. Where my blade points; legions conquer. Dark has my dreams been of late, filled with moral values and family-friendly entertainment. No longer will this plague my domain! The grim darkness of the far future shall return, by my command!"
 * Horus has one in the Warhammer fanfic PRIMARCHS:

""That's right. I am the of the. I can with my thoughts. I more  than you can even count. I can. And you are going to calm down and listen to me.""
 * In Luminosity, Elspeth, whose powers are all based around effective communication, delivers a supremely spoiler-heavy one.

"Hello, I'm the Doctor."
 * There's one Dollhouse crossover (Name? Link?) where just as the Big Bad is bearing down on a hostage (also evil, but more experienced in the crossing-over universe's conventions), the hostage warns that he better surrender, because an acquaintance is coming and is going to say the four scariest words in the universe, and goes on for quite some time about how he needs to give himself up now, despite holding the high ground, because once he hears those four words, he is dead meat and has no chance whatsoever, not even for mercy. This is, naturally, followed by the acquaintance arriving and saying those four words:

""I am not some innocent Bureau mage. I am a Wolkenritter. Hell followed in my footsteps once. I am nightmare, I am hatred, I am rage and the death of worlds. Now do you understand why you should never have sought to see how far I may be pushed?""
 * The lead-up is a conventional example, and unusual in that it turns the perfectly ordinary introduction into one as well.
 * In the Service's originator/extra material Monsters has Signum explaining why making her angry is bad, while in the midst of torturing someone by turning unnecessary bits of their body to ashes.

""My pack is strong. You may have taken many of us, but not all of us are gone, and you will not take another! I will show you their strength, for I carry it on my back! I will defeat you for those that have fallen!""
 * In the Service itself gives us the introduction of the Immortal Order. Worse yet, they mean it. “We are the Immortal Order. Defeat is temporary. Death is meaningless.”
 * A Numbered Existence gives us Sette's take on her job: "When nightmares have their own bad dreams, they dream of me."
 * The Alpha Houndoom in Poké Wars: The Exigence says this prior to battling the Golem leader.

"Takato://moves his right leg forward and clenches his right fist// "What did you do to my friends!" Takato (Thoughts): "Hey…how did that sound?" : "Oh, dear God…""
 * Takato from the Tamers Forever Series FREQUENTLY attempts this, though it invariably comes out as Narm both In-Universe and out

"Rika: You're underestimating us Gogglehead! Takato: No Rika, You're underestimating me."
 * However, he does get one genuinely epic one during his battle againgst Rika.

"Dalek Sec: I COME FROM A PLACE WHERE GODS ROAM A-MONGST THE STARS, WHERE THERE ARE BEINGS THAT COULD E-RASE ALL OF RE-AL-ITY WITH BUT A ME-RE THOUGHT, THAT COULD BEND TI-ME TO THEIR WILL AND FREE YOU FROM HAVING EVER BEING BORN!! YET, NO MAT-TER HOW PO-WER-FUL THEY ARE, THEY ALL FEAR THE SAME THING. Kyubey:You? Dalek Sec: NOT ME. A WO-RD; IT IS A WO-RD THAT CAU-SES SUCH FE-AR, THAT E-VEN THE LORDS OF TI-ME ARE SENT TO THEIR KNE-ES. Kyubey: And what word is that? Dalek Sec: EX-TER-MINATE!!!"
 * A Hero has Dalek Sec Giving one to Kyubey:

"Kakashi: "As her Jounin sensei, that means that I am now her next of kin until she refiles her paperwork in the Ninja Registration Office. And that means that if you or your father or your sensei try to take her from me, I can have you all arrested and court-martialed. Were you aware of that? And believe me, little girl, if anyone tries to take Sakura from me right now, there will be grave consequences indeed. Because what Sakura needs right now are the people who love her, and would do anything for her, and want what is best for her more than anything else. She doesn't need a selfish little girl trying to play at being a grownup, who wants to be seen taking care of her more than she wants to actually care for her. And Sakura doesn't need to be used as an excuse, and for you to attempt to use her grief as a ploy to get Sasuke's attention disgusts me. Ino: "I… I…" Inoichi "Now wait a second, Hatake." Kakashi: "But I'm not just Sakura's sensei. Do you know what else I am?" Ino: "A… y-you're a Jounin?" Kakashi: "Mm. And I'm something of a legend in the shinobi world, did you know that? I've been inside each and every hidden village in the elemental continent and gotten back out again, and I've been listed in every single bingo book in existence for longer than you've been alive. More than half of those books give the order to immediately retreat upon sighting me, you know, as I've slaughtered entire platoons of enemy nin without any back-up. I've spent years in ANBU, and have accepted more S-ranked missions than any two Konoha ninja before me combined ever have, and you should know that I have a perfect mission record." Asuma: "That's enough, Kakashi." Kakashi: "No, I wasn't finished. I have seniority over both your father and your sensei, both in rank and in years of service to Konoha, little girl, yet both of them are older than I am. I've killed more, bled more, and lost more than either of them. I'm better than them, both individually and combined. And I should tell you, little girl, that if someone tried to take Sakura from me just now, I wouldn't bother being nice enough to let a court-martial go through. No, I'd use every ounce of the skills I've earned to make whoever took her regret it. Now tell me, little girl. How are you and your daddy and your sensei going to make me give Sakura to you?""
 * Naruto: Myoushuu no Fuuin gives us this gem when Ino tries to bully Kakashi into letting her look after Sakura after her parents die:

"Harry: I know you now And Death is not something I will ever embrace. It is only a childish thing, that the human species has not yet outgrown. And someday... We'll get over it... And people won't have to say goodbye any more... And someday when the descendants of humanity have spread from star to star, they won't tell the children about the history of Ancient Earth until they're old enough to bear it; and when they learn they'll weep to hear that such a thing as Death had ever once existed!  I will end you if I can, by the power of mind and magic and science. I won't cower in fear of Death, not while I have a chance of winning. I won't let Death touch me, I won't let Death touch the ones I love. And even if you do end me before I end you, Another will take my place, and another, Until the wound in the world is healed at last..."
 * Harry Potter and the Methods of Rationality gives us a combined Badass Boast and Crowning Moment of Heartwarming:

"Sean: We're Power Rangers! We don't quit, we don't surrender, and most importantly, WE DON'T LOSE!!!"
 * Power Rangers GPX; if you thought Power Rangers was silly, think again:

"Doom: [smiling] I have seen enough horror in my life that I'm not impressed. I have walked the road through Hell itself. I have loved monsters and had my monstrosity loved in return. I am not afraid."
 * From Only Smile When I Lie, a Doom/Loki Thor fanfic:

""I am Aayla Secura. ""
 * In A Sticky Situation series, specifically the Digimon/Star Wars crossover sequel "Secret of the 327th", there is a particularly impressive one that covers plenty of events in Aayla's life both prior to the story's beginning and during the fanfiction itself.

""Tsunade-san," the Daimyo did not bother to argue with his samurai, "If I asked you, how long would it take you to incapacitate my guards and toss them outside?" "Assuming you didn't want them seriously injured?" she prompted, and the Land of Fire's ruler waved his hand in agreement. She looked around at the twenty, thickly muscled, well-armed, and heavily armored men. Then she shot the ranking warrior a smug grin. "Thirty seconds," she answered, "forty, tops.""
 * Short but sweet in A Growing Affection. The Daimyo of the Land of Fire wants to talk to Tsunade alone, but his bodyguards protest, leading to this exchange:

"He spread his arms wide, grinning madly. "Look around you, Haleigh! Your world is crumbling. Your Pokemon have been defeated. I am the true Master. You see, I'm the one people are truly afraid of. I'm the one who makes the likes of Giovanni and Ghetsis tremble in their sleep. I can wipe the floor with anyone. I've defeated Cynthia and Naomi effortlessly!" Rayquaza rose up from behind him, glaring at Haleigh. "Do you really think," he whispered softly, "that you will stop me?""
 * Josh delivers one in Blood in The Water:

"Kross:'Fate. Destiny. Predestined. SHUT UP! My brother died in my arms today, and you tell me it was fate? I'll make my own fate in this world. You just declared war on the Nightroad clan.And this is war like any other. The last man alive wins! And I won't rest until I track down and destroy every one of you and then take the fight to your pathetic god! This is my declaration. MY DECLARATION OF WAR!!!" (lightning flash emphasizes the word war) Kross: Fifty of you left, huh? At this rate, it'll take until dawn to crack all of your skulls. (cue Slasher Smile)"
 * Kross and Rain: Cursed Souls has two, both from Kross, and both inspired by Berserk

"Dr. Eggman: A foolish choice, you stupid horse. Those who dare stand in my way will be destroyed. Now, be a good little horsy and back off! Twilight Sparkle: First of all, I’m not a horse, I’m a pony. A unicorn to be exact. A very powerful unicorn who has defeated more powerful enemies with the help of my friends. Second, you terrorized Ponyville, attempted to harm innocent bystanders, and caused widespread destruction on our peaceful town. But the biggest mistake you made was destroying MY library. Now, I’m going to show you why getting a unicorn angry is a very bad idea! "
 * The My Little Pony: Friendship Is Magic/Sonic the Hedgehog crossover Chaotic Harmony; Dr. Eggman finds out harshly what happens when you tear through a certain purple unicorn's home.

"Watson: “If your master’s actions destroy him whom I regard as — as the best and wisest man I have ever known… make no mistake that I shall hunt down, to a man, everyone who played a part in his destruction.”"
 * In the Deliver Us from Evil Series, Dr. Watson delivers a passionate and pretty scary one to a captured Mook...

""I'm The Doctor, and these (MLP Mane Cast...and Zecora) Are my friends. And we are going to stop you. Understood?""
 * Time Lords and Terror has the Doctor delivering a subdued but effective one to.

": You float one inch towards my daughters, I'll kill you and seal your spirit in one of my horseshoes!"
 * During the "Origins" arc in the Pony POV Series,  gives one to Discord right before  :

"Bellatrix cackled. "And you think you can stop me this time, little girl?" "You know the power the Dark Lord knew not?" Hermione said. "It's me!""
 * The final lines of chapter 79 of the Harry Potter fic Lady Archimedes:

""There's too much on the line for me to ever give up and... more than that, I've decided that this is what I want to do. So... I'll do it, whatever it takes, and go as far as I possibly can. Before all of this, I was always uncertain of everything and I guess I still am in a lot of ways, but at least this much I'm sure of. That asshole is up to something and he and the Grimm are playing some messed up game with the entire world—and whatever they're after, they've killed countless innocent people to get it. But... if this is a fucking game, then I'm going to win it, because I'm the fucking Gamer.""
 * Jaune Arc in the RWBY/The Gamer crossover, The Games We Play: