The Binding of Isaac: Rebirth
637 Achievements
800-800h
Steam
A Pound of Flesh
Complete the final chapter with Cain.
14.3%
How to unlock the A Pound of Flesh achievement in The Binding of Isaac: Rebirth - Definitive Guide
See
The Options? achievement in The Binding of Isaac: Rebirth worth 16 pointsComplete the final chapter with Isaac.
for a full guide on reaching and fighting the true final boss.