An interesting thing about a Talason is that they're usually made by a willing sacrifice. Old or sick people would be 'built into' the new house and their spirit or specifically shadow would become a part of the house.
It manifests itself as a ghost that guards the house but he can be evil.
It is also possible to forcefully build a man into a house. Criminals were feared in slavic society since their spirits can remain to haunt the earth as vampires or other demons, so intead of cremating, the people would measure the criminal's shadow with a rope. That rope would be built into a house transforming him into a new Talason, binding him to that place. Once the rope becomes the house, the criminal has about 40 days before falling ill and dying. This signals the transition of his shadow. Some feuding tribes that had a member who fell ill would sometimes accuse a rival tribe of secretly stealing his shadow and declare war
1 more thing. Once christianity arrived, the priests would obviously not allow a man to be sealed alive in a wall ( imagine the clergy's reaction upon hearing that ), so the bride and groom were afraid of being the first to get married in a church since it would 'make it their own' and make the groom a Talason after he dies. Being the first to marry was considered a daring and noble act.