Gary has two requirements to accomplish for him to move from dark warrior to something else. he first has to reach level 50 and upgrade his class to queen of which he will achieve by breaking out of the prison.

I don't think that Gary will eat or kill her unless she is affiliated with the Phoenix gang which I doubt. however, I think Gary will still get some power up from this fight, a skill. he already has a fast regeneration ability therefore, I am leaning towards lighting affinity and leveling up of his current skills like lethal bounce.