Casshern Sins (2008)

S1E23 Those Who Return

Their duel rages on, a brutal symphony of steel and raw power. Casshern and Dio know that only one will walk away from this, yet neither flinches from the grim truth. They have accepted that this endless conflict is all they were ever meant to be—a purpose carved into their very souls. In this final clash, the line between victory and oblivion blurs, and they find a strange, somber peace in the knowledge that their existence was always destined to end here, locked in combat.