The Joker (a faceless entity in a tattered circus coat) explains:
Chishiya is thrown into a zero-sum game with 10 copies of himself, each representing a different moral choice he never made. The real Chishiya must kill them all — but each death removes a part of his personality (empathy, cunning, fear). By the end, he’s nearly hollow. alice in borderland season 2 cracked
: Every player in the games was a victim of a massive meteor strike in Tokyo. Their time in the Borderlands occurred during the single minute their hearts stopped in the real world. The Survival Link The Joker (a faceless entity in a tattered