Duncan then took on the resposibility of becoming Richie's teacher as well as his friend. Duncan taught Richie everything he knew his technique when fighting another immortal and the rules once a conflict started between 2 immortals. Duncan also had to teach Richie that although he was now an immortal he wouldn't live forever unless he kept his senses about him and watched his back and his head!
Duncan was also ther for Richie's first quickening and he explained how it felt for him on his first quickening. Duncan and richie got into alot of situations together and it was exciting to find out how they ggot themselves out of the mess they were in and it was also great to see the friendship between then get stronger and stronger.
In season 5 things were getting a little tough for Duncan and this evil spirit called Ahriman came and was wrecking havoc on Duncan's life, at one point richie and Joe were really starting to get concerned for Duncan's Metal stay once he started to see people he'd behead already even Horton who just wouldn't seem to die anyway in the season finale duncan was fighting Ahriman to the best of his ability and Duncan began seeing a red glow in every's eyes Richie came into he room to try and help Duncan and Duncan thought that Richie was part of the demons he was seeing and took Richie's head:-( Duncan was never the same.