Chrono-Gladiators are one of the finer examples of Grimderp within the 40k Universe. Chrono-Gladiators are cyborgs, sometimes made as a criminal punishment by the Adeptus Mechanicus, whose life span is determined by a pre-set self-destruct program. You thought their names have something to do with Time Travel right? Nevertheless, Chrono-Gladiators are not Servitors in the sense that they are from former people who still retained their personalities and identity, is just that these suckers did something that really pissed off the AdMech to warrant such a fate.
As they are programed to die at a set amount of time, the only way they can extend this is by killing. Each battle they win moves the timer a fraction on the self destruct deadline, driving them to kill in order to keep living. As you can tell, having a unit that dies if they don't kill is an extremely inefficient way of using armed infantry in the advent of war due to the fact that, oh I don't know, all of them will die before they even make it in the battlefield. Thereby making them as pointless as a weapon with a used-by date of one hour.
In hindsight, maybe it was a much better idea for the AdMech to follow the Arco-flagellant route instead of constructing troops with expensive equipment that would die during Warp transit. The only way these creations could make sense and sound less stupid in this Universe is that they actually play by their namesake as gladiators rather than a military unit.
The Chrono-Gladiators as aforementioned, have a pre-set destruct deadline, which is only extended when they are in battle, as they thirst for life itself. Every second the Chrono-Gladiator is not in combat, their life-timer ticks down the seconds towards their death. The death clock's life timer can only be reversed by the chemicals released in the sensation of shedding blood. How the machine can tell the difference between normal euphoria and murderous delight is unknown. When the death timer ticks towards self destruction, the Chrono-Gladiator suffers debilitating effects, which shedding blood counteracts. When it reaches zero, the destruct timer explodes the Chrono-Gladiator's heart.
Chrono-Gladiators are fitted with numerous bionic weapons and attachments, with almost no equipment other than that necessary for killing (though some are known to have been equipped with rebreathers). Almost all are fitted with some form of power weapon, usually power claws or gloves, which sometimes have ranged weapons attached to them. Most are fitted with several injector implants and are pumped full of a lethal cocktail of combat stimms (notably Slaught and Spur) and bio-enhancers; their sanity is questionable, as the only life they can lead is one of constant battle and bloodletting.
As a result of their complex cybernetics, weaponry, equipment and short life span, Chrono-Gladiators are expensive and difficult to obtain which begs even more questions on why even have a built-in self-destruct timer in the first place? If they were as cheap and disposable as the fucking Tech Thralls than maybe, just maybe it could alleviate some of the very dumb logistics and construction behind this ergonomic nightmare.
Tl;dr, these things are dumb and makes absolutely no sense even by the shit-poor standards of WH40K. Not only does the creation of these things not make any sense, it even fails to be Grimdark due to its nonsensical nature. Chrono-Gladiators is a good example on what NOT to do when trying to create a grimdark setting. If you make it grimdark just for the sake of grimdark without any rhyme or reason, than it would just end up looking satirical at best, edgy at worst.
Known Chrono Gladiators
Krieger 'Krash' Thrax is the big guy featured at the top of the page, and appeared in the Inquisitor RPG . He was originally the bodyguard of a tech-smuggler, caught by a Skitarii patrol on Gryphonne IV and sentenced to become a Chrono-gladiator. After his initial discomfort he soon settled into his new role, managing to beat the self-destruct clock every time. He was obtained by Madame Inquisitor Jena Orechiel after much difficulty and expense, who instructed him to kill her son Kal Jerico to put his abilities fully to the test.