bio-transference power able to drain living energy from people, weakening her initial target while moving that energy into herself or others, either enhancing the second target's inherent abilities or transferring the initial target's abilities into the second
Probationary membership presumably revoked after her betrayal.
Cressida was a retcon character introduced in Avengers (6th series) #1.1 - 5.1, taking place behind the scenes between Avengers (1st series) #16-17. Her origins remain unknown. She was known to the Stranger and claimed to be seeking revenge on the Avengers, but why remains unrevealed.