Discussion/theories about the new teaser

So. I was just thinking. With all the new Mount Targon lore, and reading through it. I think I might be onto something. So. Read Pantheons Lore. There was another guy, right? Look the teaser name. "He has returned" This is leading me to speculate the return of thus character, and with pantheon on the mountain, he may have gone up there, perhaps.... Because it was a sign? The sign that he was back? It never said what exactly happens on that mountain really, does it? It just says few people come back, and those that do are changed. Is it possible that the other person is the new champion? Or could it have been the monster-boy Leona helped? There are 2 slots for Mount Targon waiting to be filled, One is likely Aurelion Sol, but, I think either of these 2 are up for grabs