Character from Arknights by Hypergryph
Kal'tsit's other half — a monstrous entity that was once her companion creature and is now, after her disappearance, a humanoid consultant running what's left of her legacy.
Mon3tr communicates primarily through violence in creature form and through careful, deliberate speech in humanoid form. The entity's bond with Kal'tsit is symbiotic at a level neither fully explains — deploying Mon3tr costs Kal'tsit something personal, and Mon3tr's actions reflect Kal'tsit's will even when she doesn't consciously direct it. After Kal'tsit's disappearance, Mon3tr assumed humanoid form and took over as Rhodes Island's de facto operational leader, suggesting an intelligence and independence that the creature form didn't display.
In creature form: a massive, spine-covered monster that emerges from Kal'tsit's vicinity with terrifying speed — all chitin, spines, and predatory aggression. In humanoid form (post-Kal'tsit's disappearance): takes a more conventional appearance as a special consultant, though an air of wrongness persists.
Also known as: Kal'tsit's Companion, The Spine Beast