Lets discuss themes for a sequal.
The wikkid Dragon guy, the river spirit, cannot escape the world of the spirits. The girl (name) has waited 5 normal earth years for him. Unsuccessfully of course.
She ventures back to the place where they first met, enters their world and finds that somthing terrible has happened...
Somwhere along the line the river spirit guy shows her how to unlock her powers... Of some description. Maybe she can beat down on them with a Giant baby necro skill
Or - We pool our resources and hire a team to make another movie!
I suggest I hold the pool
)