The Eight Brothers (８人兄弟, Hachi-nin Kyōdai) are a group of eight identical brothers (a pair of twins and two groups of triplets) who have all taken up relationships with girls from alternate species. Their experiences with their respective girlfriends are featured in the Living with Monster Girl comic series.
Drives an overseas pickup truck, with its roof removed, so that his girlfriend can drive with him.
In order to keep up with his girlfriend's sexual appetite, he trains physically and spiritually to increase his stamina.
Is in a relationship with a Mermaid, whom he first met while spending a holiday at a seaside lodge.
Repeatedly returning to the lodge to spend time with her, he uses a diving helmet to take walks with her at the bottom of the sea.
While waiting for a visit from Brother 1 and Lamia, his girlfriend uses her body slime as a type of sexual lotion play. In the end the pair are caught by their visitors and Lamia ends up interrogating Mermaid on how to do "lotion play".
Later has an interview where he explains his family tree and the comic series in general.
Once a week, he drives out to a well to draw clean water for his girlfriend to absorb.
Owns a red pickup truck, where his girlfriend rides in the water-sealed tray for safety.
Tends to have "slime baths" where his girlfriend turns to liquid within the bath tub and he lowers himself into her. It took a while for her to gain enough self control to prevent her body from digesting him on contact.
First meets his girlfriend when she throws a basin of blood on him while he was on the verge of dying due to a weak body. Falling in love with him, the dullahan started living with him and protected him from the grim reaper.
Uses a bicycle for transport but lives in a city full of hilly roads.
While considering getting a motorcycle license due to the strain of carrying his girlfriend, in full armour, up and down hills, after his girlfriend loses her head and ends up having to carrying her head in the bicycle's front basket, he opts to get a car license instead.