'Strzok' is a real person, though that may not be his real name.
It seems pretty clear now he is a CIA fixer, probably assigned by Brennan to the FBI in 2015 to cover up the Benghazi email mess. And then bury the U1 information. And then work on Trump.
Comey and McCabe must have known this all along. It's unclear whether Priestap or Page knew, until maybe much later.
Anyway, that is why Strzok is still around. He can't simply be fired by the FBI, and he's the connection between the FBI investigations and a domestic CIA operation to coverup international fuckups and corruption.