When Yuugi mentions being bullied and beat up, Kaiba's mind distinctly recalls his hand in that. He remembers the feel of the impact his briefcase made, when he'd clocked Yuugi across the face with it.

He remembers...something ugly, uglier than who he is now, which is impressive.

It feels like a restitched part of his heart has been prodded with something barbed. Why does that memory feel so painful? Kaiba hadn't regretted his actions back then! But after what Atem had done, the situation that had left him comatose...some things had felt different.

Kaiba felt a prickle of guilt.

"Hn," he hums quietly to himself. Then, "I can see your issue. But the truth is, if you could house the soul of another person, who are they to judge whether you needed protecting? The Puzzle chose you. That should have been enough for them."

It wasn't for you, his mind supplies sneeringly. But that wasn't important, because at the time, Kaiba wasn't a friend, or even a potential ally. He was an adversary.