Here is the full list of all 20 Revelatio achievements.
Defeated Tubalcain.
Defeated Leah and Rahel.
Defeated King Phanuel.
Defeated Elieus.
Defeated Yana.
Defeated Appaim.
Defeated the Savior.
Corrupted Tubalcain.
Corrupted Leah and Rahel.
Corrupted King Phanuel.
Corrupted Elieus.
Corrupted Yana.
Corrupted Appaim.
Corrupted the Savior.
Unlocked all of the Black Prophet's abilities.
Unlocked all of the Successor of Evil's abilities.
Unlocked all of the Saint of Sin's abilities.