|Appeared in|| Kick-Ass|
- "You guys never saw "One Night In Spiderman"?"
- ―Marty [src]
Marty Eisenberg is Dave Lizewski's friend.
Marty is best friends with both Dave Lizewski and Todd Haynes, who he regularly hangs out with during school and at their local comic book store. When Dave questions Todd and Marty about why no one has ever took it upon themselves to become a real-life superhero, Marty remarks "Dude, if anybody did it in real life, they'd get their ass kicked. They'd be dead in, like, a day." which Todd agrees with, but Dave is unconvinced.
When Katie Deauxma pursues a friendship with Dave after he was "found naked and beaten in an alley" and believing that he is gay, Marty tries to convince Dave to tell Katie the truth, which he eventually does, and during this time, he becomes close to Katie's best friend Erika Cho, and attempts to "convert" her into a comic book reader by guiding her through various comics. Marty and Erika eventually become boyfriend and girlfriend.
Inspired by Kick-Ass, Marty decides to join the superhero club and creates his own costume. It didn't take long for him to join superhero team Justice Forever, under the alias of "Battle-Guy". After making up a lie of his parents death, he is swiftly accepted into the team and becomes a former member.
However, his true identity is soon revealed after he accidently spoke with his true voice, with Kick-Ass present, and was soon identified by the fellow member. Marty is forced to tell the others that his story about his parents death was a lie, and he felt "out of place" as everyone else had a good story. He is quickly let off the hook by team leader Colonel Stars and Stripes.
After finding each others' superhero persona, Kick-Ass and Battle-Guy regularly teamed up and patrolled the streets and rooftops, often talking about their mutual friend Todd. Eventually, the duo decide it's time they reveal their superhero identity's to Todd, asking him to join Justice Forever.
Marty is with the team during their first bust, after Colonel Stars and Stripes located some mafia members holding prostitutes in their apartment. He was Night Bitch's saviour during the raid, protecting her with his shield from what would of been a brutal knife hit.
His second battle was unluckily enough between Justice Forever and the Toxic Mega-Cunts, on the night that ended it all. Whilst playing a vital role during the battle, he knocked down a member of the Toxic Mega-Cunts before being knocked down by another member of the Toxic Mega-Cunts but protected by Todd, formerly known as "Ass-Kicker". Not long after he swiftly made his way to the hanger rooftop, only to join Kick-Ass and the rest of the team.
- Todd Haynes - Friend.
- Dave Lizewski - Friend.
- Colonel Stars and Stripes - Leader.
- Doctor Gravity - Teammate.
- Night-Bitch - Teammate
- Remembering Tommy - Teammate
- Insect Man - Teammate.
- Erica Cho - Girlfriend
- Katie Deauxma - Friend
Behind the scenes
To be added