That answer wasn't quite enough to satisfy Ulquiorra, but he hadn't expected better. If Zexion considered the man worth bringing in, then that would have to be enough. It certainly sounded as though Vexen represented a lot of potential value, which would be why they'd been tasked with retrieving him.

If he turned out to be too difficult to work with, he would either have to stop being difficult, or be eliminated. Since they already worked with Szayel, he'd have to be extraordinarily difficult to be too difficult.

Ulquiorra nodded his head, just once.