I cant belive your giving it a 13+!!!
In my jr school they had loads of them!
Like "The New Adventures"!
When my teacher told me and my class to do a libery visit, me and my mates just sat on the chairs, layed back and piked up a DCcomic. Bye the time we had left the school, we had proberly read all of them!
And tell me, who Doesnt like Batman Robin Spiderman The x-men super man ect???
.... 5+ because it has some girls in bikinis in some of them.
These are fictional characters, don't play up to the real world. To some kids, they might want to put it in action in real life. Especially kids that are unstable. Use it as an escape from their real life.