Complex sentence: Some locals claim that he summoned a troll using old Nordic Runes to help him; it is that Troll who resides on Hairy Man Road, still there after the hermit's death.
Split into simpler sentences: Some locals claim that he summoned a troll using old Nordic Runes to help him. It is that Troll that resides on Hairy Man Road, still there after the hermit's death.