He was trying to save his world from the Reapers, AI that are stuck in the cycles of destruction, but got sidetracked by the Multiverse and the endless possibilities. That's how he ended up in the vicinity of Supergirl, falling from the orbit right along with the intricate escape pod. Now he had to deal with the suspicions of the DEO, the enormous amount of different alien species around he needed to be prepared for, and the complete lack of funding, that could actually result in his death. It didn't help that one of the most dangerous aliens he didn't want to ever cross, was a girl that saved him the first day they met.