Vadim

Vadim is a nechist' spirit - a domovoi - who inhabits Lada's house. He claims to be older than her, and regards the house as more his property than anyone else's. Vadim became more active after Lada returned from her expedition to the Volkhv Encampment, though similar things seemed to be going on in other houses in Aleksandrovka.
Vadim caused Lada, Vashti and Irina some harm, but after many entreaties, told Lada that if she expected the trouble to stop, she had to start treating him with the respect he deserved. She also needed to conduct a ritual to bring back her dvorovoi, as the old one, in the form of a goat, was killed by Vashti during an altercation. Vadim seems to take many forms. He sometimes appears as a black cat. He can also become invisible at will.