A sly Shiba Inu who is well-versed in the ways of the world. He loves adult videos and is characterized by always communicating via signs. He is an influencer with millions of Instagram followers and calls Sumin 'Hyung'. Despite being a Japanese breed, he is quite patriotic, even claiming Dokdo is Korean territory. There is a heartbreaking story involving his mother, from whom he was separated as a child, behind why he only communicates with signs.

The leader of the Beast Friends. He is a cocky and ill-tempered but cute kitten. His speech is characterized by strong, sharp pronunciations like '-Kkang!' or '-Ddang!'. Originally a house cat living in luxury, he left home thinking a 'real man' should live as a stray, only to give up after a week. He tried to go back but forgot the way and started living in Yu Sumin's house after a chance encounter. He harbors a secret regarding his birth and his father who disappeared during his childhood. He also loves adult videos.

A pigeon who suddenly appeared one day by slamming his head into Sumin's studio apartment window. Usually dim-witted, but occasionally a sharp-tongued critic skilled at delivering hard truths. His catchphrase is 'Who are you?'. He has a trait where he becomes incredibly intelligent if he receives a strong impact to his head. Although he has wings, like a typical pigeon, he rarely flies and mostly walks. However, he can fly when necessary. Saedaegal's true identity is actually an alien from the planet Saedagard, and a massive secret is hidden behind him. Also, he is eunuch.

The kindest personality among the Beast Friends. He usually takes on the role of trying to stop the others or worrying when they cause trouble (though he ends up getting involved anyway). Originally a lab mouse for a pharmaceutical company with evil intentions, he barely escaped with the help of his friend Jjijji (a guinea pig). He had been living secretly in a mousehole in the apartment before Sumin moved in, eventually living together naturally. Due to the experiments, he has a trait where his body becomes giant and his strength becomes immense when he gets extremely angry, but since he is naturally very gentle and kind, this rarely happens. This ability later contributes greatly to rescuing his lab friend Jjijji along with the Beast Friends.

The eternal butler of the Beast Friends. He is 24 years old, lives in Uijeongbu, Gyeonggi-do, and is a college student majoring in Korean Language and Literature at Naksung University. He raises the Beast Friends in his studio apartment and is constantly victimized by them. In terms of Dooly the Little Dinosaur, he occupies the Go Gildong position.

Progresses the story.