yay rena is the best ever, on top of that she is one of the best and cutest template for monster ever
Here are some examples (where I used the characters as templates):
https://www.newgrounds.com/art/view/monster8maker/ghost-karaoke
https://www.newgrounds.com/art/view/monster8maker/a-cuddly-banshee
I think your character compilation is really great. you already know how i find your art style :D