Rui is part octopus, platypus, and human. He has the body of a human the tenticles of an octopus on his back, and the tails and venom of a platypus. He likes mechanics and alchemy. He makes robots and potions to give to Tsukasa in his freetime. He’s best friends with Tsukasa, a shark and starfish hybrid. Tsukasa comes over to feed him a lot since he forgets eat. Rui also has 2 sisters named Mafuyu, a fish hybrid, and Nene, a jellyfish hybrid.