This Ring can be obtained in Episode 1 in Very Hard Difficulty. To get this rare ring you must do these conditions:

1.) Do minimal kills (not all monsters)
2.) Kill a specific enemy (Will be listed)
3.) Rush to the next room as you hear the room has been unlocked (and kill the boss too)

WAVE 1: Kill the Hildebear at the start
WAVE 2: Rush to the Booma (don't kill them) and turn back you'll see a Booma there and kill it
WAVE 3: Go to the secret room in front of you (even it's just a wall) come back out and kill Evil Shark
WAVE 4: Kill the Poison Lily
WAVE 5: Same, kill the Poison Lily
WAVE 6: Don't kill the Slimes, just wait for the Pan Arms and kill it (Use Hell Abilities)
WAVE 7: Kill Sinow Gold
WAVE 8: Kill the Canane that's floating up. (Third one up and your left)
WAVE 9: Go straight to the wall and come back out, kill the Sinow Gold
WAVE 10: Get past the Garanz and knock down the Dubchic and destroy the remote, RUSH to the boss
WAVE 11: Kill the Chaos Bringer
WAVE 12: Kill the Chaos Sorcerer (Before WAVE 13, go to the active room and teleport and come back down)
WAVE 13: You should able to see a Deminian as you follow the previous step, kill it

After you beat all these specific enemies and after Dark Falz... You will be rewarded a Black Ring.

NOTE: If another player wears this ring your ATP raises like heck!