Hōsenki I

Hosenki was a demon that InuYasha and his friends met up with at his father's grave at the gate to the netherworld. He told Inuyasha to slay him to get a jewel shard, but Inuyasha was distracted by Naraku's miasma and had to save his friends. Noticing how loyal and protective Inuyasha was, he taught Inuyasha a new move for the Tessaiga, the Kongōsōha. Inuyasha used the move against Naraku, and also ended up getting the jewel shard from Hosenki.