Kieros was a young Vietnam War veteran and became paralyzed. Apocalypse appeared to him one day and offered him the ability to move and to get revenge on those who had tossed him aside. He accepted the offer and was indeed given the ability to move again, which allowed him to use his mutant power—the ability to create explosions through kinetic contact, usually by clapping his hands together—in Apocalype's service as his Horseman of War. He often bickered with one of the other Horsemen, Famine, and disliked her total lack of obedience. War liked to take control of situations and during their first confrontation with X-Factor, attempted to lead the other Horsemen. Famine and Pestilence refused to obey his orders and flew off to do their own business. Soon after, Death took over leadership and the Four Horsemen learned to ride as one. During the attack on Manhattan, War immediately attacked Cyclops and was later teleported back to the ship by Apocalypse, where he fought several more X-Factor members. He was eventually defeated by Iceman. Apocalypse then grabbed War and fled.
Later, during the X-Cutioner's Song
story arc, War attacked Colossus
and Iceman, but soon fled after Caliban
grabbed Jean Grey
and Cyclops, handing them over to Apocalypse, who was really Mr. Sinister
in disguise. The X-Men
sought out the Horsemen and War was presumably defeated in combat.
A New Life
Much later, War was apparently abandoned by Apocalypse and left in the hospital, once again paralyzed from the neck down. Archangel took his newfound powers and healed War of his wounds, giving him hope to start over with a new life.
Age of apocalypse
He is member of the first roster of Horseman of Apocalypse together with Candra
. He appears trying to take control of the government's nuclear weapons base at Cape Citadel under Apocalypse´s orders. He uses his explosive energy in order to burst the first line of defense of the facilty. Along with Death he stays outside trying to defend Gideon´s directive, he fights against Iceman and Colossus but he is defeated.
He has the ability to create explosive energies which burst forth from his hands.
X-Men : The Animated SeriesWar appeared in three episodes of the series the first being, Come the Apocalypse, where War was selected by Apocalypse and transformed into his Horseman; the second and third, Beyond Good and Evil Parts 3 and 4, where he fought alongside the other Horsemen when the X-Men sought out Apocalypse’s Lazarus chamber. Instead of using his mutant abilities in the latter two episodes, he used an energy-projected sword.