Father's Old Enemy: Ryukotsusei

This episode reveals that it was Ryukotsusei who was responsible for th death of Inuyasha's father. He inflicted a wound on Inutaisho that never healed. In the film "Swords of an honorable ruler", we learn that Inutaisho had just left his fight with Ryukotsusei before learning that Inuyasha's mother Izayoi was in danger. He had a brief exchange with Sesshomaru before leaving quickly to save her without regard for his wounds. Though it's never explained what exactly happened during Inutaisho's fight with the Demon, there is a remote possibility that Myoga rushed to his master's side to warn him of the pending fate of Izayoi. Inutaisho knew that she was pregnant with his offspring and cared for her a great deal; enough to get distracted which could have led to his injury. After sealing Ryukotsusei he went to save Izayoi with Myoga hanging onto his fur, who continually tried to warn him that his wound would kill him if he didn't stop to recover. He ignored...