Tōma Inumaru served as vocalist for the band NO_MAD, which competed in the Black or White competition only to lose to TRIGGER. This defeat prompted him to swear off serious singing entirely, focusing solely on revenge against TRIGGER.
Though he professed hatred for both IDOLiSH7 and TRIGGER, his naturally friendly disposition surfaced when he carried an unwell Riku Nanase on his back.
His resentment toward idols was manipulated by Ryo Tsukumo, who leveraged NO_MAD's rejection by former fans to recruit him into Tsukumo Productions. This resulted in Tōma joining ZOOL.

As ZOOL's leader and dual center, he gradually opened up to his teammates, becoming the group's most proactive member.
His initial reluctance toward idol work softened, particularly after a birthday surprise from his ZOOL teammates. They arranged a photoshoot highlighting his "cool and mature" side and presented a roast beef sandwich cake, acknowledging his preference for meat over sweets.
Deeply moved, he expressed gratitude, acknowledging that while he once rejected serious singing, performing with ZOOL gave him new purpose. He vowed to keep singing with them "until my voice is hoarse and I'm all skin and bones," emphasizing their determination to persist regardless of public reception.

Camaraderie and playful teasing mark his ZOOL relationships. He uses nicknames like "Mina" for Minami Natsume and "Haru" for Haruka Isumi, while they call him "Inumaru-san" and "Toma."
Torao Mido often likens him to a dog due to his surname "Inumaru" (containing the character for 'dog'), a connection reflected in his stage costume's collar, added at Ryo Tsukumo's suggestion.
Tōma dislikes "light, bright, dazzling things," contrasting his efforts to project rebellion, though his inherently good nature frequently shines through his words and actions.

He stands 176 cm tall, with a birthday on November 29, making him 20. He prefers meat and rock music and dislikes multi-compartment bags.