The Womb
Next upDefeat Mom.
Reach Depths II and defeat Mom.
Sources:AchievementsWomb
Achievement
Defeat Mom's Heart or It Lives! on Hard mode as The Lost.
In-game: “Unlocked a new co-player baby.”
Sources:AchievementsHard modeMom's Heart
Defeat Mom.
Reach Depths II and defeat Mom.
Sources:AchievementsWomb
Defeat Satan 5 times.
After: The Womb
Defeat The Lamb as Isaac.
After: The Womb, The Negative
Die in a Sacrifice Room while holding the Missing Poster.
After: Missing Poster
Defeat Mom's Heart or It Lives! on Hard mode as The Lost.
After: The Lost, The Womb