Resasuke is a daydreamer who has an unusual fascination for canned coffee and plants.
Just like Retsuko, Resasuke's appearance is based on the Red Panda. Unlike Retsuko, Resasuke has light yellow fur and lacks the distinctive white stripe under his eyes. He has white ears, white and tan around his muzzle, tan fur tufts in his ears, a mole under his nose, and his mouth is always ajar. Resasuke wears a white dress shirt, blue tie, and matching gray suit jacket and pants during work. While out on dates, Resasuke wears a white shirt, blue suit jacket, khaki-colored pants, and brown shoes.
When Retsuko was in love with him, she sees him differently than how he truly appears. His eyes are angled with stars in them, the white markings are shaped like eyebrows, his mole moves to under his left eye, and his voice becomes deeper.
Resasuke is a daydreamer at best who constantly spaces out to the point of frequently missing his train stop and being late to work. Resasuke also easily gives in to peer pressure, most notably when he dated Retsuko despite not having feelings for her simply because Manumaru told him to. He is very quiet, usually doesn't speak unless spoken to, and doesn't seem to read social cues. His studio apartment is full of plants, which he takes good care of and sometimes talks to, showing that he prefers interacting with plants over people.
It doesn't appear that Resasuke had any romantic feelings for Retsuko, and although he didn't hate Retsuko, he only agreed to date her because Manumaru told him to. Manumaru directed Resasuke on what to do throughout their relationship, but even so, Resasuke gave very little to their "romance." Retsuko broke up with him after only dating for a short period of time, realizing that she was idolizing Resasuke and that he wasn't really enthusiastic about her or their relationship.
Manumaru and Resasuke appear to be buddies, and both work in sales. Manumaru is actually one of the few people Resasuke socializes with, and the two seem to be close. He is easily annoyed by Resasuke's constant questions and has a hard time explaining things to him. Manumaru considers Resasuke to be a "potted plant" (Someone who doesn't strive to do new things) and has to move Resasuke's head to get him to pay attention, which Resasuke either doesn't notice or simply chooses to ignore.