Frumpkin

Frumpkin is a feline familiar of Caleb Widogast. He is voiced by Matthew Mercer.

As a magic cat, Frumpkin can appear, disappear, and/or re-appear at Caleb's whim. Caleb can issue telepathic commands to Frumpkin. Caleb can also use Frumpkin's eyes and ears, though this renders Caleb's body temporarily blind and deaf.

Familiars are technically not beasts, though it is unclear whether Frumpkin is a celestial, a fey, or a fiend. (Though fey is implied by Caleb as of episode 3)

As of Episode 3, Frumpkin is currently in sparrow form.

Trivia

 * Liam shared his vision of Frumpkin on Instagram.
 * Caleb's ability to take control of Frumpkin is similar in function and appearance to a warg on "Game of Thrones".