Either Bst or just plain AIDA-infected. I've only seen the trailers and a bit of discussion on Trilogy, so I figured the new form was probably similar to Haseo's new look. Hence the Bst label.
AIDA Atoli, Bst form I'd assume would be Haseo only sence he is an Adept Rogue. They had something like this in a character book for G.U. too, the answer would be there if someone can find it...