Batman: The Merciless #1

Synopsis

On Earth -12, Ares had fashioned a new helmet that amplified his powers. The Batman and Wonder Woman of that world, who were romantically involved, led the final battle to defeat Ares, but it cost Wonder Woman her life. Grief-stricken, Batman donned Ares helmet gaining his powers and becoming the new God of War. Recruited by the Batman Who Laughs, he travels to Earth 0, where he confronts a joint task force of the heads of A.R.G.U.S., S.H.A.D.E., the D.E.O. and Task Force X and turns them all against each other.