I have a story outline that's mostly complete, but there's one character I feel could use some more development.
He's a symbiotic lifeform that grants supernatural abilities to his host. He hasn't had a host in over a century, though, for two reasons:
1.) The host must be willing and at least several years old.
2.) Most people nowadays are raised with a prejudice against his kind (which are mostly giant monsters), and even a "willing" host will have a subconscious resistance.
He has a human friend, and when she meets someone from another world (who wasn't raised with this prejudice), she tricks the guy into being the host by promising that (through a somewhat complicated plan) he can get back home. The girl has her own motives for this (she could use the super-powered help), and eventually she realizes what she is doing is wrong.
Right now, the symbiote (his name's Crow) is more of a plot device than a character. I want to give him his own motivation, and to change over the course of the story. What could I do here?