Tobi comes off as rude and somewhat abrasive at first appearance in the manga. Rei notes that he looks displeased. Tobi offers advice and help to Rei which shows that he is not as unpleasant as previously shown. He seems to be slightly annoyed by Noppo and other small Zingai.

The animator of How to Eat Life described him as listless with an 'unpleasant' look on his face.

On the day of his high school entrance ceremony, Rei is suddenly assailed by a feeling of languor. When he wakes up, he finds that his surroundings are filled with things that could not be called human. In a town where strange phenomena continues to stretch, a group of lonely youths have their encounter. 

Music video directed and animated by Marie Yasui for the song Inochi no Tabekata by Eve.

Tobi Otogiri, a second-year student in middle school, doesn't spend much time with his peers. Instead, he mostly chats in secret with his pal Baku, a mysterious backpack he received the day he last saw his older brother. Or at least, Tobi thought his chats were secret until a girl in his class named Ryuuko suddenly mentions Baku. Soon, strange things start happening at school, and the two of them realize the cause might be a creature only they can see… Thus begins an adventure blending reality and fantasy, human and nonhuman—a story about life eating life.
 
(Source: Yen Press)

Music video directed by Marie Yasui for the track Fight Song by Eve. 
Note: The song featured in this music video also serves as the twelfth ending theme of the Chainsaw Man anime.

Otogiri Tobi, a 2nd grade middle school student, spends his depressing days searching for his missing older brother alongside his inhuman companion, Baku. Tobi used to rarely speak to anyone besides Baku, however one day after his classmate Shiratama Ryuuko suddenly approaches him, his life begins to change...? This is an adventure surrounding the "human" and the "inhuman" that a lone boy faces. 
(Source: Comic Walker, translated)

Music video animated by Marie Yasui for the song Insomnia by Eve. 

Note: The song featured in this music video also serves as the theme song of the 2024 live-action movie "My Home Hero".

Music video animated by Marie Yasui for the song Sayonara End Roll by Eve.