I'll fill this out completely as I go back to fight the old ones and get up to the higher levels.

Name Level Cost Reward Treasure Theme
Rednose 2 25s 100 FP and 100s Charm Mishmash
Alfhild 11 45s 340 FP and 180s Brooch, Pearl, Painting Runner
Atomisc 16 55s 470 FP and 220s Onyx, Necklace, Tapestry Submarine
Sadie 20 65s 630 FP and 1,700s Diamond, Bust, Tiara Royal
Vaclein 28 105s 1,010 FP and 430s Sword, Scepter, Helmet Ironclad
Diabolito 38 115s 1,470 FP and 470s Ghostly