Why are so many people jumping to conclusions? Chiaki may have valid reasons to have scars. Is there a tag for it? Maybe if it was tagged, people wouldn't freak out so much. I personally don't see it as offensive and I have gone through some shit like self-harm myself...
About the characters, they are so damn cool and hot. I love tomboys, I wish there was more yuri with them! I think you can see that they're girls, maybe Karen (oops, I mean Kiri, haha) is kind of a reverse trap, but she's so cute. I hope the artist makes more comics or even just art of these two.