Ryuukotsusei (竜骨精)
Background
Ryuukotsusei is ruthless and has a mask that exists on his forehead through which he speaks. His attack is Raigekidan (Thunder Attack Bullet), which is the form of a giant white ball of explosive energy, which he emits from his dragon mouth instead of fire, and could easily have defeated InuYasha with a final blow if InuYasha wasn't able to learn and use the Bakuryuuha just in time to defeat the dragon. Myouga's protests reveal that it was Ryuukotsusei who inflicted the severe injuries on InuYasha's father that were the main cause of his death shortly after sealing Ryuukotsusei away.