Complex sentence: Some souls were not able to settle down or were not welcomed in Tuonela, and they continued haunting, i.e. bastard children who were killed and buried outside a cemetery usually ended up as permanent haunters of some place.
Split into simpler sentences: Some souls were not able to settle down or were not welcomed in Tuonela, and they continued haunting. Bastard children who were killed and buried outside a cemetery usually ended up as permanent haunters of some place.