I’ve spotted numerous references in the game like the moji who is Goku or the rockoid who is The rock, but with new monsters that came recently like G.F Mizu who is easily comparable to Hatsune Miku with her hair, or in certains dialogues like in the 6th chapter in online story in the last realm, 2nd battle, the opponent says “useless” multiples times, comparable to Dio Brando in JJBA.
Bastia is based on Bastet, the Egyptian goddess of love and home.
Persephia is based on Persephone
Nightingale is based on Florence Nightingale the famous doctor
Tyrfina is based on Tyrfing, a cursed sword from Norse mythology.
Lucifelle and Gabrielle are a reference to Lucifelle and Gabriel
Lilithia is based on Lilith
Jeanne D’Arc is a reference to Jeanne D’Arc
Nyx is based on the night goddess Nyx.
Botan-Douji is based on Shuten-Douji, an oni from Japanese mythology
Orochi is based on the Japanese god Yamanata no Orochi
Carmilla is based on the lesbian vampire novel called Carmilla
Gremoris is based on Gremory, a demon.
Asmodia is based on Asmodeus the sin of lust
Apollonis is based on the god Apollo
Charybdia is based on the sea monster Charybdis