>>3936347The idea is that Jayce is the last human being left on Runeterra (except maybe Singed) because Viktor succeeded in conquering the world. Now, Jayce has wandered the world and found nothing, just people being fused into buildings, the ground etc. So he returns home for one final confrontation with Viktor -- understanding that it is going to be his last fight ever -- but Viktor ends up sparing him.
There was going to be a twist ending that he was a mannequin after all and Viktor only let him think that he was a human (out of guilt) but that's probably too hardcore.
The subplots I'm writing about are them trying to restore the world to the way it was and also ending up in the AU and bringing the signs of the contamination from the main universe in with them along the way.