Turin is a veteran of many battles and skirmishes against the forces of Morgoth. Perhaps, this makes him overconfident in his abilities as a warrior. So when the forces of Morgoth gather at Ered Wetrin, he feels Orodreth must send his army to wipe them out. Alas, it is a mistake that causes the fall of Nargothrond. He also loses Finduilas, whom he loves.