Ok this isn't a crack (as of yet) but hear me out:

Alamo by Alec Benjamin should be stain's theme song.
The song is all about standing your ground and staying true to what you believe while everyone else is trying to say you shouldn't believe it and I feel like it sums up his morals and how people see them pretty well. It also says that believing something no one does is like being trapped in a cage and I feel like that sums up Stain having to be on the run and hiding all the time pretty well as well. And also this is my favourite song by him and stain is one of my favourite characters (joint with Spinner, second to Magne) This entire thing has felt like something you'd have to write in Primary School but I didn't know any other way to phrase it so yeah.

Oh here's the song by the way:

[There should be a GIF or video here. Update the app now to see it.]

Ok. I think that's all I've got so..So long and good night!