So since it seems everyone's giving their characters themes, I'll just jump right on that bandwagon!
..though, admittedly, it was kinda difficult finding a fitting one for Ryg since there's really not much about him other than his backstory. Nevertheless, I managed to find something for him anyway.
Ryghedro
[SPOILER="Holy Diver"]The Song itself is about things that aren't always what they seem; Things that appear good can be bad in reality, and things that appear bad on the outside have good locked inside. You know, that old quote: 'Don't judge a book by its cover'.
I feel like that's most fitting for Ryg, as; he appears most of the times as human to disguise his alien form and, despite being an alien with powerful abilities and a justified reason to despise humanity, has neither a killing tendency nor harbours hatred towards humans for what a group of them did to him and his species.
Rather, he uses his abilities for a good purpose, adapting to becoming a vigilante, if not also leading a thieving life to avoid getting a job and spending more time in crowds than necessary, stealing only what is necessary, when it is necessary and what he can't get out in the wild by himself.[/SPOILER]