Abusive Parents/Comic Books

Batman sometimes dips into this, depending on the writer. All Star Batman and Robin is the worst offender (Batman forces 12-years-old Dick Grayson to live in the cave and eat rats), but it's sometimes seen in the regular universe as well. Bruce can go from the world's best father to the cruelest monster imaginable within 3 issues.
DC comics, Deathstroke/Slade Wilson. Even putting aside how he was heavily involved in the deaths of both of his sons, you could make a case for this solely for Slade's youngest child. Rose Wilson has spent most of her life since her dad discovered her existence trying to deal with his epic-scale emotional manipulations. After rejecting her at first, he stormed back into her life by having her foster family killed and her kidnapped. Then he lured her into being his apprentice and injected her with the same super-soldier serum that gave him his meta-human fighting abilities (crossing over into Physical Abuse as such). Rose eventually had a psychotic break and carved out her own eye to prove her loyalty to him.
- Again, crosses over into physical abuse when Deathstroke implants a chunk of kryptonite (which can still give humans cancer) in her eye socket so he could use her as a weapon against Superman.
Luornu Durgo, aka Triplicate Girl, founding member of The Legion of Super Heroes. Father abandoned her and her mother, mother was an alcoholic, and she was horribly abused to the point of torture by caretakers, as her "condition" (her three bodies having separate personalities) marked her as a "freak". Only her grandmother gave her emotional support, as she believed the "condition" was healthier than most Carggites believed (she claimed Luornu's behavior indicated non-conformity and independence, and that not showing it was like withholding feelings and living as an introvert). Her luck only changed when she escaped the asylum she was held and found by the billionaire philanthopist R.J. Brand (who would later help found and fund the Legion) who sympathized with the sad, disheveled girl and helped her leave Cargg. Becoming her legal guardian was rather easy, given his political and economic influence on the planet, especially with knowledge of their juvenile psychiatric treatments.
Rorschach is subjected to this in Watchmen to quite some degree. In a flashback, we see his mother openly providing her services (she's a prostitute) in front of him, and when he wanders in by mistake, driving off her client, she slaps him across the face and says she should have had an abortion. Scarring stuff, indeed.
- What he ended up seeing as a kid returns throughout the comic as a pattern on walls, in his childhood drawings, in various shapes (including the shape of his mask at times), and actually is echoed at the very end when Dan and Laurie make the same shadow in a far more peaceful situation. Additionally, Ozymandias ends up alone, casting a singular shadow on the wall in contrast to the double ones shown throughout the book.
- Speaking of Laurie, her parents -- all three of them -- are... not very good at it either.
Wally West didn't exactly have the best parents. His father demanded to be given the love that he never got as a child from his family to the point where he (Rudolph West) became the abuser.
Wolfsbane's father helped a group of religious fanatics brainwash his daughter into a programmed killer to be sent after her teammate, Angel. It blows up in his face in an ironic way.
- Given the level of emotional abuse he subjected her to growing up (his hiding the fact that it was he that sired her upon her supposed harlot of a mother being the least of it) and his leading the mob that shot her and tried to burn her at the stake when her powers kicked in, the above shows that he's nothing if not consistent.
When Harry Osborn got his first bike, some boys stole it from him. His father, Norman Osborn , took it back only to break it into pieces in front of his son and tell him that this is what happens to the things that he can't guard. Years after, because of his toxic father, Harry started to use drugs and it is part of the reason why he became the second Green Goblin. And what Norman is doing currently makes him king of this trope.
- In the recent American Son Story, we learn Norman had sex and knocked up Harry's current girlfriend and made Harry think it was him. Worst father ever? You decide.
- Norman's own father was also abusive to him. It must run in the family.
  - While Harry was going insane as Green Goblin II, it was heavily implied that he was grooming his son to be just as much of a maniac as him, but it never seemed to be physical.
Oh, and there's Black Tarantula, Spider-Man's ex-enemy, who, in the '90s, tried to take his son from his ex-wife, both of whom were under the protection of another criminal. He attacked that criminal's headquarters alone and defeated everyone who got in his way, including Spider-man. However, when his ex-wife reminded him how his father had destroyed his childhood by forcing him into training and asked if he wanted the same for his son, he just walked away, leaving them alone.
Howard Stark, Tony Stark's father, was verbally and emotionally abusive. As a child, Tony respected his father greatly and wanted to please him. However, in spite of Tony's genius, Tony's reluctance (and inability) to assimilate his father's "ethics" caused Howard to resent and despise his son. Howard's rejection hurt Tony deeply, and although Tony has long since lost all respect for his father, he's never entirely gotten over it, as shown in Iron Man: Legacy of Doom:

(in Mephisto's Realm, Howard Stark's spirit appears before Tony)
Tony: Y-you?
Howard: Losing again, eh, boy? You always were a wimp. Never had the stones to do what had to be done.
Tony: I always tried to do what was right!
Howard: Brilliance isn't enough. You'll never reach your true potential worrying about consequences. You're weak.. [...] You're no son of mine.

Tony: I'd heard it all before. But the pain was still enough to distract me from the physical task at hand.

(Howard lunges; Tony flees, unable to attack his own father)

Howard: COWARD! You were my greatest shame, but I'll make a man of you yet! I'll beat it into you!

(later, after Howard is defeated)

Tony: You can't kill something already dead. I'd been telling myself that for a long time.

- In Legacy of Doom, Howard is also physically abusive, but it's unclear whether or not Howard ever physically abused Tony in life. (Although Tony doesn't seem too surprised by Howard trying to kill him; but then again, Tony is in hell.)
When Knuckles was born, his parents soon begin arguing about the proper way to raise him. It eventually got so bad that his father Locke divorced his wife and took sole custody of the boy so he could raise him to be a guardian. Locke essentially abandoned his son when he was ten years old, forcing him to fend for himself for years with little or no contact with other people. Locke insists that all of this was done to build character and make Knuckles a better guardian by forcing him to do things himself. In truth, he had Knuckles under close observation the entire time he was "abandoned" and often expresses regret at causing his son so much grief, but he still insists he was only doing his job.
Squee's dad openly despises him and often talks about how Squee's birth ruined his life, Squee's mom is too drugged out to remember she has a son half the time (the other half she believes he's already grown up and moved out.) The series ends with them signing him over to a mental hospital for experimentation.
Jason Rusch's Firestorm (pre-reboot) was physically abused by his father.
The very first time we see Chase Stein of Runaways, his dad is punching him in the face for getting bad grades. It's implied that this sort of thing has been happening regularly for most of Chase's life.
Marvel Comics' Tabitha Smith/Boom-Boom was abused by her father until she ran away from home. This is a pretty commonplace trope for their mutant characters.
Cassandra Cain is an odd case. She received plenty of emotional support and positive reenforcement from the man who raised her from birth to around age eight (who was also eventually revealed to be her biological father), however shooting her until she learned to get out of the way and preventing her from learning language so that segment of her brain would read bodies instead qualify as abuse under any definition imaginable.
Brenda from the Jaime Reyes Blue Beetle comics. Her father reportedly knocked her around on a regular basis at first, but then upped the ante and put her in the hospital when the police questioned her about Jaime's disappearance, causing Brenda's crime boss aunt to have him killed.
Obsidian's adoptive father was physically abusive when he was drunk. Unfortunately, he was drunk all the time. During his time as a villain, Obsidian killed said adoptive father.
Marvel Comics' Bullseye possibly has an abusive father. Whether it's true or not, the guy is dead.

Psychologist: And you say your father beat you?
Bullseye: Yes, until I was fourteen.
Psychologist: Hmmm. I see. And what happened then.
Bullseye: (kills psychologist with a voice recorder) I killed him.

- His mom apparently wasn't too great of a woman either.

Bullseye: (as he becomes a Dark Avenger) Pity I killed my mom in high school- she would've loved this. (beat, as everyone stares at him) Kidding. She wouldn't've cared.

Carnage, another crazy supervillain from Marvel, has serious issues with this. At last one of his parents was abusive. He said once that his mother tried to kill him, but his father saw this and killed her. However, another time he said that his father killed his mother, when he was trying to kill him. Possibly his grandmother was that same kind of person. For both father and grandmother it didn't end well.
Darkdevil from Spider-Girl, by a gambling alcoholic uncle. Not to be confused with his other uncle.
The Flash villains Captain Cold and his sister, the Golden Glider, were abused by their father. Years later, Cold had the chance to kill his dad, but couldn't bring himself to do it and let Heat Wave do the honors.
Funky Winkerbean -- In a Backstory, Bull Bushka (the former school bully turned physical education teacher) reveals that he was physically beaten by his father ... hence, the reason why he tormented the strip's main protagonist Les Moore all these years.
- Other storylines have seen Susan Smith (the girl who had a crush for her teacher, Les, and maintained it as she became his colleague) being beaten by her boyfriend while in high school; and Lisa Moore (who was beaten by her one-time boyfriend, the one that got her pregnant as a teen-ager).
The DCU's Damage was sexually abused by his foster father.
According to Elektra: Assassin, Elektra of Daredevil was sexually abused by her father at the age of 5, after which she was told it had never happened until she more-or-less believed it.
One of Ben Reilly's girlfriends, Elizabeth Tyne, who decided to become a Self-Made Orphan.
- Made worse in Spider-Girl of all universes, where it's implied that after turning herself in, Elizabeth spent the rest of her life in prison for killing the jerk. Oh, and her son ends up being (physically) abused by her family, too.
Meet Devin Irons, the father of four children, whom he severely abused and then offered as souls in a pact to a Plague Bringer Demon for the power to control human minds, turning all but one of them into soulless, vicious monstrosities intent on bringing death and destruction to the Old West. He killed Silas Irons only father figure after he came to confront him for tying his son onto a statue, bloody and beaten, and painting "sinner" onto his chest. His crowning moment of assholeness comes when he brings his own wife, now a mindless flesh-eating ghoul, back to life as a lure to bring his adult children back to complete a ritual that will make him immortal.
Then there's Bruce Banner's father, Brian. He'd been abused by his father, leading Brian to believe his father was a monster, that he had inherited the 'monster gene', and that any children he had would be monsters too. Brian initially chose to ignore Bruce, believing him to be a monster in the making. When it became apparent Bruce was a child genius, Brian saw his worst fears confirmed, and started beating both Bruce and his mother, Rebecca. After several years of abuse, Rebecca attempted to escape with Bruce, but Brian killed her and intimidated Bruce into saying Brian hadn't done anything to them. The truth only came out when Brian got drunk and boasted about what he'd done. Brian was locked up in a mental institution, dying shortly after release. End result? Bruce developed multiple personality syndrome - and after a certain accident with a gamma bomb, his personalities became the various Hulks. And Bruce (accidentally) killed him. In a recent story, Banner himself admits it might not have been accidental. He's back from the dead and in Devil Hulk form in the Chaos War tie-in.
Darkseid is all over this trope. He has 3 known sons, all of whom he treats badly to various degrees. He feels nothing but contempt for Kalibak, ignoring, mocking, and blasting him with Omega Beams whenever it suits him. His other son Grayven is an outcast. Oddly enough, the son Darkseid favors most is Orion, the one he sent away to be raised by his enemies. This didn't stop Darkseid from killing Orion in the opening of Final Crisis.
Felix Faust manages to be the worst father in comics with one act: selling his infant son's soul to a demon for power. Luckily (well, sorta), the demon Nebiros decided to screw over Felix and gave the kid the power instead -- after taking the soul. Turning your own son into a soulless abomination of the universe in a selfish bid for more power takes abuse to a whole new level.
The Red Skull from Captain America (comics) may be the worst father in comics. When his daughter was born he tried to throw her into the ocean because he didn't want a female heir. He was convinced to allow her to live by one of his servants, but demanded she be raised without love. Skull treats her more like a servant then a daughter, heaping emotional and physical abuse whenever he can. Also when his daughter was injured on a mission, the Skull seemed not care about the welfare of his daughter, instead finding the situation amusing. Even worse he used a machine to Mind Rape his daughter, in order to "educate" her. Red Skull really does earn his Complete Monster status with this type of parenting.
Norbert Sykes, alias The Badger, was beaten, saw his dog shot and was eventually raped by his stepfather Larry. This left him with multiple personality disorder, a violent streak a mile wide and an obsession with the name Larry.
Jonah Hex's father Woodson Hex abused his son both emotionally and physically and ultimately sold him as a slave to the Apaches.
In Strangers in Paradise, Katchoo's step-father raped her on her fifteenth birthday (Later dialogue would imply he actually considered this a gift) and would repeatedly beat her in the time following. Her mother, meanwhile, refused to accept the truth and told Katchoo to stop making up these vicious lies about the sweet man who cares for them. The physical abuse was bad enough, but the complete lack of any support from her mother was what finally drove Katchoo to run away, where she eventually wound up in Los Angeles and under the sway of Darcy Parker. Believe it or not, things actually went down from there.
The retellings of Two-Face's (i.e. Harvey Dent's) origin have this present, largely being physical with an emotional element. The origins of the "Two-Face" persona come from a twisted game Dent's alcoholic father would play with him, based on a coin toss; heads, Dent's father would beat him senseless, tails, Dent would be off the hook. The catch was that the coin was a double-headed one, and Dent never won. The idealistic part that hoped the coin would land tails one day would go on to be Harvey, while the cynical part that knew it never would became Two-Face.
In the IDW incarnation of the Teenage Mutant Ninja Turtles, Casey Jones' father is one of these. In fact, it is the very first thing the reader finds out about him.
Irredeemable: Tony was originally found by a broken woman mourning the death of her child that she had just accidentally let get killed. And she would repeatedly try to kill Tony in various other ways, failing because Tony is a Superman expy, and really even then didn't know what was going on until finally trying to go for Pater Familicide in the garage.
Flash Thompson's father was an alcoholic who beat his son, who never showed him any respect or affection (in life, anyway). It helped screw Flash up something serious.
It was hinted that Loki's biological parents were neglectful and downright abusive. He managed to get his revenge, though.

Loki: You will never strike me again! NEVER!!!