Per Degaton (Earth-2: Post-Crisis)

"What happened to Per Degaton? Per Degaton? Uh... the Flash banished him to an alternate timeline."

- Stargirl and S.T.R.I.P.E.

Per Degaton was an enemy of The Flash and a former member of the ISA.

Biography
At some point, Per Degaton battled The Flash and the Justice Society of America until he was banished to an alternate timeline.