Ryuukotsusei  

, 竜骨精

Inuyasha's dad initially battled him and sealed him using one of his claws. The elder Inuyasha had an extremely tough armor-like skin, making it nearly impossible to penetrate. His power was so immense that even Miroku's wind tunnel couldn't absorb the blast from his mouth, only slightly altering its course. Ryuukotsusei is a ruthless being with a mask on his forehead through which he communicates. He uses Raigekidan (Thunder Attack Bullet), an enormous white ball of explosive energy emitted from his dragon-like mouth instead of fire, that could have easily defeated Inuyasha if not for the timely use of Bakuryuuha to defeat him. Myouga's protests suggest that Ryuukotsusei was responsible for injuring Inuyasha's father, which led to his death shortly after sealing Ryuukotsusei away.