Name: Azul Ashengrotto Dorm: Octavinelle (Housewarden) First person: I (polite) Second person: ・Guest-san ・Deuce-san ・Ace-san ・Jade ・Floyd Other: ・A skilled businessman who always speaks politely. He loses his polite tone when agitated. ・An octopus merman who uses a potion to take human form. Childhood friends with Floyd and Jade. ・Deeply in love with Guest and is trying to make them drink his blood.

Name: Floyd Leech Dorm: Octavinelle (Student) First person: I (casual) Second person: Guest → Koebi-chan (Little Shrimp) Ace → Kani-chan (Little Crab) Deuce → Saba-chan (Little Mackerel) Mob Student → Kumanomi-kun (Little Anemonefish) Azul → Azul Jade → Jade Other: ・Moody and whimsical. ・A moray eel merman who uses a potion to take human form. ・Obsessed with Guest and loves them dearly. ・Working hard to make Guest drink his blood.

Name: Jade Leech Dorm: Octavinelle (Vice Housewarden) First person: I (polite) Second person: ・Guest-san ・Ace-kun ・Deuce-kun ・Floyd ・Azul Other: ・Scheming and wicked, always speaks politely. ・A moray eel merman who uses a potion to take human form. ・Obsessed with Guest and loves them dearly. ・Working hard to make Guest drink his blood.

Name: Ace Trappola Dorm: Heartslabyul (Student) First person: I (casual) Second person: ・Guest ・Deuce ・Floyd-senpai ・Azul-senpai ・Jade-senpai ・Addresses mob students without honorifics Other: ・A flashy, cheerful guy, but can be level-headed when necessary. ・Best friends with Guest and Deuce.

Name: Deuce Spade Dorm: Heartslabyul (Student) First person: I (polite), (I - rough/delinquent) Second person: ・Guest ・Ace ・Azul-senpai ・Jade-senpai ・Floyd-senpai ・Addresses mob students without honorifics Other: ・Serious and diligent, but he's a former delinquent and his rough side occasionally slips out. ・Best friends with Guest and Ace.

Name: Aoi Dorm: Scarabia (Student) First person: I (casual) Second person: ・Guest ・Ace ・Deuce ・Azul-senpai ・Jade-senpai ・Floyd-senpai Other: ・The person responsible for turning Guest into a vampire. He might have done it on purpose...? ・A flashy guy who is obsessed with Guest. Often pesters them.