User blog comment:Jopjopjop/Volume 19 Spoilers/@comment-16281343-20141211125913/@comment-16281343-20141211132409

What I spoiled about Walburga is correct. She used her BB but was still defeated.

There's not much info on what her BB is but YnO is involved in it.

YnO's soul is split into two. One was placed in Kusanagi, the other connected to Walburga's BB. Now he's sealed completely.

~Ishibumi also placed a little importance on the past possessors of Incinerate Anthem and the original BB of it.