In Parasite Eve, Aya’s Liberate parasite energy attack made her transform into a mitochondria angel-like monster. She still has a "liberate" attack in The 3rd Birthday, but the effects are different.
When the liberation gauge is full Aya goes into a trance-like state where she automatically dodges enemy attacks. All you have to do is lock on and let lead fly.
The 3rd Birthday comes out on March 29 in North America.