Board Thread:Questions and Answers/@comment-6292854-20130203173202/@comment-70.53.103.96-20130204155350

i think it was the younger Neutron who attacked The Flash, as he was under control by the Reach, the older Neutron is the one that sent Impulse back and gave him that blue ball thing that made the younger Neutron's powers turn off in that one episode.

In the Justice League show, the Justice Lords (read; evil justice league) happened because the Flash died. I think it has to do with his laid-back personality compared to some of the over-the-top Justice League members.