User blog comment:Jopjopjop/Volume 18 Spoilers/@comment-122.148.181.24-20150108094051/@comment-16281343-20150110050251

Info on YnO is very scarce as unlike the other Evil Dragons, he wasn't given a physical body.

His soul was split into two: one was placed on Kusanagi Sword (Volume 18), the other used by Walburga for her Balance Breaker.

The only thing known to him is that he has 8 heads.