Dad never goes in the pool. Roman only sees him swim once, very early in the morning, when he's not supposed to be up. It's the first time he's glimpsed his father's bare back, and the scars are shocking for a child to see.
"Dad, what happened?"
"None of your damn business," Logan growls at him. Roman knows better than to push the subject.
Some of his fear must show on his face, because Logan puts a hand on his shoulder — Roman thinks he might push him in the pool — and says, almost gently, "Don't mention this to the others, alright?"
He doesn't mention it. He kind of forgets about it, to tell the truth, until he overhears a conversation between his dad and his Uncle Ewan some years later, about their own cruel uncle, the one they lived with. Oh, so that's where the scars came from.
Logan is nothing like his Uncle Noah, Roman knows that. He never hits hard enough to scar.