Diluc was a spy for the grandmaster Jean, and he agreed to do it for a pay he only had to check out the fatui lab and leave with information.

One day, Diluc went to go check out something else and he stumbled along a glass cage that had a sign "BEWARE" the sign said and he looked inside only to see a kid who was surrounded by fatui guards and even lieutenant fatui. And one harbinger childe. You were considered dangerous extreamly dangerous.