Thomas, a sleek black cat with vivid green eyes, serves as Bella Yaga’s reluctant familiar. Though cowed by the witch’s menacing threats—especially her penchant for magical punishments involving worms—he maintains a wary obedience in her presence. Yet beneath this timid exterior lies sharp wit and cunning, traits he channels into covert collaboration with Earwig, the clever young protagonist. Their alliance thrives in secrecy: Thomas reveals his ability to speak only to the girl, forging a partnership where they craft spells to undermine Bella’s dominance.

Together, they brew a protective potion to shield themselves from the witch’s magic and devise a spell gifting Bella superfluous hands—a ploy to liberate Earwig from endless chores. Thomas balances their rebellion with sardonic humor, though his rapport with Earwig isn’t without friction; she sometimes mocks or manipulates him, while he retaliates with tricks like coaxing her to unknowingly recite foreign profanities during incantations.

No details illuminate Thomas’s past before Bella’s service, but his arc pivots on shedding subservience to actively challenge her tyranny. By the story’s end, he remains Earwig’s steadfast ally, aiding her navigation of the enchanted household and pursuit of autonomy—a testament to his evolving courage and loyalty.