It took a while for Zabuza to put two and two together. He had seen the marks appearing and fading on his body, had gotten used to them shortly before he had met the boy. He thought little of them until the pattern was made clear by a spontaneous stop at a cheap hot springs.

He paid as little attention to Haku as possible normally. The boy was an extension of his blade, nothing more. That changed when he saw the bruises on his torso, marks of the hard training he was committed to doing every day. Zabuza plotted each one, unable to believe his eyes. They matched the marks on himself perfectly. Every bruise and cut, every scar. They all lined up exactly with his own which could only mean one thing.