You- [And here Guy jabs a finger between Asch's brows] have a little dent here because you're always scowling. It'll be a wrinkle in five years, tops. You also have a diagonal scar across your stomach and two over your shoulder, plus the three from Eldrant. You don't open your eyes as wide as Luke does, and you don't fling yourself around on the bed when you sleep like he does.

Luke has a scar on his left elbow from where he tripped and skinned it, and two burn marks on the ball of his palm from when he touched the burner in the kitchen. His hair is lighter and a lot wilder than yours, and his writing is messier, though he can actually write quite well if he puts his mind to it. He isn't as particular about his appearance as you are, his balance isn't as good as yours, but he's faster than you.

...I can go on.