Apocalypse Zero(1996)

Apocalypse Zero is an anime series set in a post-apocalyptic 21st century where siblings Kakugo and Harara fight demons and monsters using advanced combat training and Zero armor—mystical suits forged from the souls of fallen warriors. When Harara is corrupted by the dark power within his armor and turns to evil, Kakugo becomes humanity's last hope. As the only fighter alive with both the skill and equipment to match his brother, Kakugo must confront Harara in a brutal battle that will determine the fate of what remains of civilization. The series blends intense action with dark supernatural elements as it explores themes of corruption, sacrifice, and the bonds between family.