Buso Renkin/Awesome

Kazuki

As for protagonist, of course, Kazuki gets plenty. Most memorable that comes to mind is when he fights an opponent with an undodgeable, and unblockable attack, that will kill him instantly if it hits him. He answers by deactivating his lance and blocking it WITH HIS HEART (true it was a replacement heart made of a near indestructible alloy, but...)
Also the scene near the end of the series, where, upon realizing the Big Bad couldn't be beaten, he makes a charge with his lance so powerful IT SENDS THEM TO THE MOON
In the manga there's a scene where Kazuki has defeated an enemy alchemist warrior. His comrade takes his Kakugane, and is prepared to leave with it, but Kazuki stops him and gives it back to his ENEMY, effectively saving his life.
Nearly his entire second fight with Captain Bravo.
- In particular the scene where he breaks through Silver Skin by smashing the point of his own lance, so he can follow through on his thrust and get in a second hit with the fragmented head of his spear, before the armor regenerates.
- "I WILL DEFEAT YOU AND I WON'T LET YOU DIE!"
In the manga, after Ikusabe brings Kazuki the defeated Papillon, Kazuki turns the surrounding environment into rubble with nothing but pure rage.
Kazuki is fighting Victor, who is more powerful than him, can drain energy from all living things, and has beaten even the most powerful Alchemic Warriors. What does he do? He sends Victor and himself to the moon, and precedes to fight him for the next month, only stopping when other Alchemic Warriors come up to get him. He then convinces Victor to not give up and come with him, leading to a peaceful resolution.

Captain Bravo

Where to start with this one? His very FIRST fight in the series, against a homunculus that had just made sport out of two other warriors. He proceeds to beat the living tar out of him in a matter of seconds.
- I am not.... ANGRY!
His Heroic Sacrifice near the end where he uses the Silver Skin to protect Kazuki, Tokiko and Gouta from the blast of a NUCLEAR BOMB but takes the full blast of it himself in the process.
- Literally made this troper cry when he read it in the manga, not embarassed at all to admit it. That wasn't just badass, that true hero material. AND HE LIVED THROUGH IT, YES!
This scene
The unveiling of the Silver Skin Reverse.

Tokiko

Her defeat of Maruyama, who can make his opponent's shrink down to nothing. At an inch tall, she makes Maruyama swallow her, and then makes good on her battle cry when she literally "splatters his guts." From the inside out.
Another one when she fights a Rose Homunculus. Her weapons are tangled up in the homunculus's vines, so she rips out the Homunculus's eyes with her FINGERS. Did I mention humonculi are monsters with many times the strength, speed and stamina of humans? And that Tokiko was majorly weakened from another Homunculus infecting her? Bad. Ass.

Victor

His very first appearance in the series, where he blocks Kazuki's signature attack with his palm. And isn't even scratched.

Papillion

His defeat of Ikusabe is definately up there. Faced with an opponent who can literally regenerate himself from nothing, Papillion decides that the only way to beat him is to stick his own body right in the path of where he's supposed to regenerate, in order to screw it up. Suffice to say, it works. Explosions ensue.