Dumchik is a Domovoi, a type of Fey called the House Spirits, protecting Greenside Farmstead. He lives in 'Ma' and Murom the Reaper's house, and was first encountered during Trouble at the Farmstead.
During Shadows of Greenside, he was kidnapped by the invading Shadow forces, but the visiting party saved him, though he ended up fused to a twisted tree in the Millennium Forest.
As of Not So Greenside, Pt. 2, Dumchik was found to be bound within the aforementioned tree. He wasn't quite himself, split between his kinder side and another side that had become more feral, connected intrinsically to the forest. The party completed a ritual that was conceptualised by Dumchik, but left unfinished. The idea behind the ritual was to connect Greenside to the Millennium Forest. Ezekiel Laggrond filled in the gaps using his knowledge of necromancy. The intent was for the residents of Greenside to be able to voluntarily join the empathic network, and thus have the two locations mutually benefit from cooperation.