I am everfree Picture
This is from one of my favorite stories, one called "Merely a Mare" by Ebon Mane. This is a character who is painfully complicated to say the least. His name is Ever Free, and his body is immortal, but his mind is not. Since his mind ages and decays like a normal pony's, he's forgotten many things, but he remembers two things: His name, and how much he hates Celestia and Luna. He reminds himself of these by carving his name all over his body, and by cutting out the skin where his cutie mark should be. I don't usually like alicorn oc's but he's a rare exception. The story is amazingly written with a really intriguing mythology and history that was far more well developed than many I've read. If you like stories about Luna and others with well developed characters and histories, look it up.
As a side note, I don't know why, but I always think the Equestrian alphabet we see occasionally looks a lot like one of the Elven scripts from Lord of the Rings, so that's what I used to write "Ever Free" all over him.