IMO it's
1. Mereoleona - Always showing her power in every fight.
2. Fuegoleon - Although we haven't seen much from him, he was shown to be powerful anyway.
3. Dorothy - Glamour World is all she needs to destroy anyone.
4. Yami - Obviously, everything he did was insane.
5. Nozel - Actually a pretty powerful guy. He beat Dark Patry easily.
6. Jack - I wish he did more than spamming Death Scythe but it is already pretty powerful anyway.
7. William - He was underwhelming imo, but he did show a lot of strong spells.
8. Charlotte - Only manipulates briars. She has used it well in combat, but she's not the best in strength.
9. Rill - Undoubtly strong, but not THAT strong.
10. Guldere - His attribute is rather impressive, but anytime he came on, he was trashed.
11. Kaiser - Literally saw nothing from this guy