This is a list of enemies that drop Tier 4 Rings.
Sort order is alphabetical, ignoring descriptors where it would separate otherwise similar enemies, and ignoring articles, except for any ‘groups’ (eg. Dungeon Bosses) which go first.
The enemies are:
Dungeon Bosses
Realm Gods
Cube God
Kage Kami
Oryx the Mad God
Oryx the Mad God 2
Pentaract
Skull Shrine