There are four tiny scars on Guts's wrist. They're from Griffith.
They had been fighting, play fighting really, and Guts had knocked him on the ground. Griffith had grabbed his wrist and dug his nails into his Guts's skin, hard enough to bleed. His eyes had been wide, and almost wild.
Guts thought he was going to ask him to pull him up, instead he pulled Guts down.
Guts has left no tangible mark on Griffith's body.
It's not for the lack of Griffith trying, though. Each time they fought, he let his guard down just enough so that Guts would be able to hurt him enough to scar.
Griffith's scars always healed, though.
He was never the one to accept a loss, so he's taken to consider his very skin is a mark that Guts has given him. And that's better than a tiny mark.
"Am I a terrible person?"
Griffith asks questions like these carefully, on many occasions, to the right people at the right time, to make him appear more human and unreachable at the same time.
When he asks Guts, it comes out of nowhere.
Guts puts the most thought in the time Griffith asked if he was a horrible person after the Eclipse. Before, he didn't bother telling Griffith 'no' because the answer was obvious to Guts.
It haunts him, because the answer is still the same.
Guts sometimes opens the scars Griffith gave him, and he never questions why.
Griffith still thinks his skin is a scar from Guts and obsesses over it.