Ryūkotsusei

Ryukotsusei (竜骨精 Ryūkotsusei) was a dragon daiyōkai who fought with Inu no Taishou long before the main storyline. He never was able to fully kill Ryukotsusei but managed to Ryukotsusei has the appearance of a typical dragon but with a mask on his head. This mask is Ryukotsusei's real face as it does the talking and directs the body while the u no Taishou had died from the very battle that had sealed him and that Inuyasha was his son. Ryukotsusei constantly looked down at Inuyasha calling him a 'little boy' and ridiculing Tetsusaiga on its effectiveness against him.

Abilities

 * Enhanced Strength: Ryukotsusei was able to dominate over Inuyasha for the first half of the battle, only to momentarily overwhelmed by his demonic transformation. His full power was not shown in the series, but it was enough