system
Given the following post, respond as if you're commenting on Reddit:
human
[Warhammer 40k] How did the Emperor reveal himself to humanity? Who was the first person that he revealed himself to?

So we all know that after the Age of Strife, the Emperor "emerged" on Holy Terra, revealed himself to humanity, and created the Thunder Warriors to conquer the Solar System. 

But how did he start? Did he walk up to a crowd and say "I am the God Emperor of Mankind listen to me."? Did he ask Malcador to start calling him the Emperor?
gpt
He conquered Terra. He won, he can call himself whatever he wants. 

There is a good chance he started like any other two bit despot, he was a techno barbarian fighting against other techno barbarians with varying levels of both Xeno and DAoT hardware. Which is why it took him so long to conquer Earth, everyone was high level contender. 

He just started winning and squashing all of the other warlords in the name of the Emperium and in the name of law and order. People like that kind of stuff.