Dotto serves as the eldest of the three tuxedo cat triplets known as the Black Cat Brothers, a group alternating between antagonistic and supporting roles. He possesses dark blue fur with a white muzzle and ears, consistently wearing a green shirt, red pants, and brown boots, distinguished by his pink tie with white spots.

Personality-wise, Dotto exhibits arrogance and a short temper, frequently initiating pranks against the main characters. He loathes tomatoes and harbors a fear of heights. Despite his generally mischievous nature, he displays moments of vulnerability, such as when he and Peizuri were pranked after trying to trap Karakusa inside a snowman in "A Snowman With a Cold." Dotto becomes visibly annoyed when Peizuri performs good deeds. Karakusa, the middle brother, typically follows Dotto's lead but expresses a gentler disposition, including a fondness for flowers and a desire for a younger sister. Peizuri, the youngest, sometimes shows kindness or reluctance toward their schemes, occasionally countering Dotto's impulsiveness.

The trio's characterization was later adapted for the Mole Brothers (Maruo, Sankaku, Shikaku), with Maruo mirroring Dotto's personality. Unconfirmed reports suggest the triplets were considered for localization as "Dot, Dan and Dash" in an unreleased English adaptation.