Memories
Laboratories
Laboratories had always been Vexen's center of operations since they held so much scientific equipment and promise.
Xigbar was a frequent visitor to the labs and, when he was there, talked to the older man about whatever topics interested them. Vexen put up with Xigbar's quirks because the man was still a scientist, even if he was a Nobody.
Back in Radiant Garden, he had constantly spent his time in his laboratory, only coming out for meals if Xehanort hollered his name. He also became very irritable if you dared to poke fun at his experiments.
After he became a Nobody, he spent even more time in his labs, trying to find new ways to get a heart. Finally it was Xemnas, the leader of their little group that came up with the idea to use Kingdom Hearts for their purposes. He sought to rationalize such a decision, because, after all, he was a scientist.