Hammerstein is a war robot, an ABC Warrior built to fight the Volgans. Following the war he was sent to Mars to help tame the terraformed planet, and then was sold as army surplus to Ro-Busters, an agency that used "expendable" robots to fight disasters, but later led an escape by his fellow droids. Centuries later he reformed his ABC Warriors unit to work for the alien warlock Nemesis; the group stayed together subsequently, taking on several additional missions.
Hammerstein was created by Pat Mills as one of the leads in Ro-Busters, a strip in Starlord. When Starlord was cancelled and merged into 2000 AD, Ro-Busters transferred to that title. After the success of a Ro-Busters story showing Hammerstein telling his fellow robots about his war experiences, he was spun off into a new ABC Warriors series set between the aforementioned flashback tale and Hammerstein's time with Ro-Busters. ABC Warriors eventually finished, but the team was revived years later to become supporting cast members of Mills' Nemesis the Warlock series, which in turn led to the revival of their own series.
The leader of the ABC (Atomic, Biological, Chemical) Warriors, an elite robot battle squad, Hammerstein gets his name from his battle hammer which takes the place of his right hand during combat. A Mark IV war droid, Hammerstein, was designed to fight in the Volgan Wars. Hammerstein was often hindered in combat by an emotion chip which made him question the reasons behind what he was doing giving him an almost human quality. After the wars were over, Hammerstein was decommissioned and he eventually joined the ‘Ro-Busters’ team, an emergency and disaster rescue group.
During his life, Hammerstein has been damaged many times, resulting in his appearance altering many times, his human like face was eventually replaced by a head with one central eye. This however was replaced by a modified version of his original head in the cross-over with Nemesis the Warlock, now able to remove the helmet that was once fused into his metallic skull.
It was an earlier incarnation of Hammerstein though, or at least a Mark IV droid, which has been to date the only ABC Warrior to make it onto the big screen, appearing in a cameo, in the Judge Dredd movie.
Hammerstein was first built sometime in the 21st century, (very) roughly equivalent to the real life time period of the 1980's and 1990's. Created by an engineer by the name of Jodie Jones, Hammerstein from the start suffered from his emotions going against his programming; at merely 3 months of age, he slipped into mechanical catatonia, caused by a disconnect of his programming and brain. After weeks of external bombardment by a robo-technician, Hammerstein awoke and accidentally killed Jodie in a blind fit of jealous rage (caused when the doctor tried to kiss Jodie in front of the prone robot). Since then, the war droid hasn't been much involved with females, mainly out of fear of another incident occurring (although he ended up in a brief relationship with a human slave later on).
After the Volgan War, in which many of his fellow War Droids where killed, Hammerstein was recruited to lead a group of wayward robots, after an incident where a commander was electrocuted when the robot sergeant removed the pain barrier of a fallen war droid, although it was never conclusively proven that he was responsible for it. With partners Happy Shrapnel and Joe Pineapples, they went to recruit the other members of the team: Mongrol, who was still grieving the loss of his savior Lara, Blackblood of whom Joe Pineapples disabled with a precise shot to the heart, the mutilated Steel Horn now The Mess and besting the robotic warlock Deadlock in a match, of which would keep the two teammates butting heads over their individual beliefs for many years afterwards.
The new team ventures to Mars where they defend new human settlers from the horrors of Martian nature, as well as keeping the peace between natives and humans. During this time Hammerstein is granted permission to try and have executed anybody, human or not, that does not comply with the laws established in the Mars cities and colonies. After many months of helping the settlers, the team disbands.
Shortly afterwards, Hammerstein, now decommissioned, is bought and sold to Howard Quartz aka Mr. 10 percent, where he meets and becomes friends with fellow robot Ro-Jaws. It is here that he also encounters for the first time the insane (and sometimes stupid) kill-dozer Mek-Quake. The two end up joining a rag-tag team called the Ro-Busters, where they do odds and ends in helping people and fellow robots. During this time, Hammerstein loses his base head in an accident and is given a cycloptic civilian head as a replacement.
Centuries later, Hammerstein, now battle weary and borderline suicidal, is forced to join the ranks of the Termight war squadron of robots, alongside teammates Hitaki and Mad Ronn. Following a program change, Hammerstein temporarily becomes an insane psychopath, willingly mowing down innocent aliens at the order of Torquemada, the Termight dictator and supreme overlord. Eventually, he is shot down and returned to normal, where he is then given the chance to rejoin the ABC Warriors alongside Nemesis the Warlock, enemy of Torquemada.
At the request of Nemesis, Hammerstein later on (after traveling to the edge of time to punish a version of Torquemada and first encountering the evil mass called The Monad), along with the rest of the ABC Warriors through the time wastes, a series of tubes leading to the past along a massive artificial black-hole. During this mission to repair the black hole (after Nemesis' enraged son Thoth nearly destroyed it in an attempt at revenge over being abandoned and seeing his mother die), Hammerstein meets with a quirky human slave named Terri (designated Terr-1 by her android masters, the Mekaniks). She is convinced she is a flesh based robot and believes that Hammerstein (who she calls "Craig") is the father of her newborn baby Wayne. In a moment of blind love, she betrays the robot team to her masters, but recants when they slaughter her son and try to kill her as well.
The team, after joining up with Deadlock, traverse the time wastes, dodging enemies and the Monad (who, at one point infects Hammerstein and temporarily "kills him), the team reaches the central Tomb of Zalinn, of which leads to the control room of the black hole. Once through, a fight between the members breaks out as Deadlock tries to keep the team from saving the Earth (as it defies his religion) and after a brief skirmish, both sides agree to a *fragile* truce.
The Monad re-appears, and at the end of the battle, Terri is killed, which devastates Hammerstein, who had fallen in love with her and was willing to disband the group to go stay with her. Distraught, he hands over leadership of the ABC Warriors to Deadlock, who then takes the team out into the universe to spread the religion of Khaos throughout the Terran Empire.
During this time, Hammerstein learns to bypass his programming and begins to disobey orders as Khaos infects him and his teammates. After a few years of mindless khaotic spreading (in which he learns that he is the only one of the team left with any sort of morale code), Hammerstein and the team return to Mars where they help out people stuck in between a civil war, one fought by Union and Confederate soldiers.
During this time, he regains leadership of the ABC Warriors and gains reputation in the war. Eventually, the president of the Confederacy hires a squad of lunatic robot bounty hunters dubbed the Shadow Warriors to kill Hammerstein and his team. In this battle, Hammerstein is taken hostage by the enemy robots and implanted with nano-bot snakes which start feeding on is internal structure and attack his head.
Through willpower and unbridled rage, Hammerstein is able to keep the implanted snakes from attacking his team and somehow get them to attack their creator, devouring his brain instead of Hammer's. The battle ends with a re-emergence of Steelhorn (now made from Martian crystals and invulnerable to all known damage) and Hammerstein continues to lead the battered team, despite having missing most of his helmet and head.
Recently, Hammerstein has been in a war with ex-Volgan commander Volkhan as he tried to gain revenge on the loss of his army and homeland back in the 21st century. He also is the one that admits Mek-Quake to an asylum for treatment, and tries to rescue the new recruit Zippo as he's being prepped for execution in a bat of molten metal.