Probably because Seth is hurt down there
Well maybe, but isnt it like a long time between those two events?
Not sure. The last chapters all happened in a day after all. It has been a long time for us, but maybe just a few days in the story
Perhaps Gods/demi Gods can just innately tell? Like how Anubis mentioned that as a God he just knew who his biological parents were.
HUH ANUBIS KNOWS WHO HIS REAL PARENTS WERE?
Yes, after he became a God. He mentions it in chapter 106.
Maybe he smells his stank?
How in the fuck did Horus know that Seth got raped by Jizzass??