Father's Old Enemy: Ryukotsusei

Totosai tells Inuyasha that piercing the heart of Ryukotsusei, the demon that gave his father his mortal wound, will make his Tetsusaiga lighter. Inuyasha then decides to kill Ryukotsusei.

The Demon's True Nature

Inuyasha, once again, transforms into a demon when faced with Gatenmaru's murderous attack against himself, Miroku, and the helpless women of a village. Sesshomaru then appears to see if what Boku'seno told him about demon Inuyasha was true.