Rivet was called the king of exiles-not because he got exiled, but his name didn't seem to fit him, at least to him. But then, one of his card cult followers, Chip said "you matter, just because you're a king and have a millitary name, don't feel bad about who you are". And Rivet said "thanks, Chip. I feel better about myself". now his cult guards him and tells people who make fun of his name to not bully him. He then ended up with a spiked collar, for his courage, that's why he's the way he is in the photo.
@Mint_honey