User blog comment:Stbk22/Possible Power up's/Techniques for then new group DxD/@comment-1359322-20141228030353/@comment-1359322-20150619144859

Very late on this reply since i just remembered. The reason or to be exact the origin to Tsubaki's subspecies BB works is because she merged her natural ability with her SG.

"……I have heard a bit about Tsubaki-senpai before. She was born in the Shinra-clan that has an ancient and honourable origin that purifies evils, but due to her trait that calls out to abnormal beings through her mirrors, she received a state which was basically isolation."