Millennia ago a conflict called "the Demonwars" resulted in the death of many demons in its battlefields. The souls of the dead merged into the Battlettide, a ghostly being seeking to absorb even more souls into itself. All souls who fell in battle were its targets. It also had an effect on the living in its vicinity, amplifying their adrenaline and driving them into an animalistic rage. Ensuring that ongoing battles would result in far more casualties than normal.
The ghostly being was able to travel across space, drawn towards various conflicts. At some point it managed to wipe out most of the Temploids, a race of fierce warriors. The few survivors formed the Knights of the Tempered Brootherhood, dedicated to stopping it.
In modern times, the demon Termagaira (who found itself split into two separate beings) schemed to attract the Battletide to its location and use it for its purposes. It abducted warriors throughout the multiverse and transported them to a desolate planetoid. Those abducted were fitted with inhibitor collars and forced to battle to the death, in a battlesport viewed and enjoyed by trillions of viewers. The Earth was represented by the abducted Dark Angel, Death's Head II (Minion), Hercules, Killpower, Psylocke, Sabretooth, and Wolverine. The latter two prooving particularly vulnerable to berserker rages.
As expected, Battletide was drawn to the conflict. Both the gladiators and the spectators were influenced towards mindless rages. Though Dark Angel and Psylocke were able to shield themselves and extended their shield to their closest allies. Meanwhile Termagaira was able to unify itself to a single being and have access to its full powers and memories. He immediately attempted to gain control over the mindless Battletide.
While Killpower and Death's Head were able to slay Termagaira, the threat of the Battletide was not over. It continued to absorb the souls of all those fallen in the battle. Improvising, Death's Head added the mechanical systems of a killed temploid to his own. He started absorbing the energies of the Battletide into himself, causing an implosion which seemingly destroyed them both. Killpower was eventually able to rebuilt Death's Head, though leaving the cyborg incomplete.
In Battletide II, it was revealed that the being had also survived. But was no longer mindless. One of Death's Heath's assimilated personalities, the black sorcerer Bezial had used the previous battle to take control over both the uninhabited body of Termagaira and the Battletide. He led the Battletide to campaign against worlds filled with life, regardless of whether there were previous wars on them. His strategy was to maximize its power.
With the help of the Temploids, Death's Head's was able to re-absorb the personality of Bezial into himself. The Battletide was again left mindless. Returning to its usual hunting grounds, on the edge of the galaxy.