Oh boy. Kakashi was thankfully very good at concealing his expression, and his smile remained unchanged even as Artemis brought up Haku of all people. Speaking with someone from his own world, it might not have been such a big deal to Kakashi. Even talking to someone like SubZero might not have marked the topic as particularly unsafe, as ninja had a way of understanding how the matter of death worked. But he'd literally just met Artemis, and Kakashi had no way of knowing what the boy thought of Haku. If they were actually friends, Artemis would be none-too-pleased to learn that Kakashi had been the one to kill him.

Which was why it was very easy to decide that he wasn't going to tell Artemis that little detail, much less mention the death itself, if he could avoid it.

"I do, yes. He and I are from the same world." Well, depending on what Artemis knew about Haku, he probably also knew certain details about Kakashi too. No point in hiding them. "He's a very respectable ninja, and a formidable one at that. Why do you ask?"