Psicurse's lore arc is interesting, and spoilers (I'm on a mobile device so I can't use that feature when posting).
So the Dr. Aeon SF takes the player to an alternate dimension where they meet a time jumping and weakened Psicurse, who asks for help securing the Psychronometron which in that dimension was upgraded with a stolen Ouroboros crystal from a dead Ouroboros acolyte. Psicurse wants to use that machine that is locked behind that dimension's Vanguard secured storage in Portal Corps Headquarters in conjunction with the Portal Corps Dimensional Codex, which, when used with enough energy (like Hero 1 Incarnate strength), would allow Psicurse to not only jump through time at will, but jump through dimensions at will also. This would give him the ability to fix the past and stop anyone else from preventing him from doing so at the very least. And an interesting quote comes after the player chooses to defeat him instead of helping him:
"I may be an old, washed-up, overly ambitious has-been - but that won't stop me from going out fighting! This is for Overbrook, for the Gagarin Space Station, for those knobs at Vanguard that wouldn't listen to me!
Nobody may be around to witness this, but in the end, PsiCurse will not die a failure!"
If the player chooses to help Psicurse and defeats the Vanguard, he will then absorb Hero 1's power and return the player back to their respective time and dimension (back to the Golden Roller fight). This gives the player the impression he's going to be a pretty powerful future enemy. Perhaps even one we'll get to fight on... the moon!
So when does he go from Psicurse to time-controlling, dimension hoping super god to a lowly Lost Archvillain?