Pluto, a demon hound and companion to Angela Blanc, first emerges in Houndsworth village. His natural form is a towering white-furred canine imbued with supernatural traits: fiery breath and the ability to shift into a human guise. This alternate form sports silver hair, crimson slit-pupiled eyes, sharp fangs, and black toenails, though frequent transformations leave him often unclothed. Despite his human shape, Pluto retains feral habits—crawling on all fours, relying on scent, and vocalizing through barks, whines, or howls instead of speech.
Pluto’s past intertwines with Angela, who sends him to the Phantomhive estate after he kills Henry Barrymore, a man manipulating the "Demon Hound" myth. Driven by protective instincts and defiance against control, this act hinders Pluto’s adaptation to his new home. Under Sebastian Michaelis’s wary oversight, his loyalty gradually aligns with the household, though tensions flare when jealousy over Sebastian’s preference for a cat exposes his volatile nature.
His role oscillates between asset and hindrance across pivotal events. During the Shard of Hope arc, he aids Elizabeth Midford’s rescue by blasting open a sealed tower door, showcasing his value amid erratic tendencies. Yet his fiery power proves double-edged, accidentally incinerating trees while assisting gardener Finnian—a glimpse of the chaos preceding his fate.
The Conspiracy and Revenge arc seals his doom. Tricked by Ash Landers, Pluto’s flames engulf London, destroying the Phantomhive manor. When containment fails, Ciel Phantomhive commands Baldroy, Finnian, and Mey-Rin to execute him. Their grim task ends Pluto’s life, with Sebastian later recovering his bones as proof of death.
Relationships underscore his contradictions: a destructive yet devoted entity. Finnian bonds with him, coining the affectionate nickname "Puru-Puru," while Angela’s influence echoes in his origins. His rivalry with Sebastian blends reluctant obedience with clashing instincts, framing Pluto not as malevolent but a creature guided by primal drives.