The Emperor of Mankind, also referred, ironically enough, as the God Emperor of Mankind against his will, is the ruler of Imperium of Man set in the setting called Warhammer 40k. I am not going to continue any further due to the fact there are 500+ books worth of lore and a wiki dedicated to explaining it.
Otherwise, you can simply watch the web-series If-The-Emperor-Had-A-Text-To-Speech-Device or TTS which explains the 40k lore briefly with a humorous tone to it.
The Emperor has had little to no actual presence in the tourneys themselves, more so appearing as a background character, specifically when there is a huge presence of roleplay. However, it should be mentioned that the emperor did make it through nominations in Mr. /co/lympus 2021, but was unable to pass the qualifier round with more than 80 votes.
But his main moment came to light in Mr. /co/lympus 2020, where he was a major roleplayer figure and a digit rival with Gwen and Simon. Even more infamously, he appeared in the infamous picture of Jack's and Simon's wedding, making anons scratch their heads to this day as to why he is even present in the picture.
The Emperor surprisingly enough managed to qualify for King /v/ 2022, in which he got seed 84 with 144 votes. He however wasn't so lucky as his opponent was Jack Garland, the then to be King /v/ 2022 but also one of his closest allies towards combating Chaos and thus succumbed to him in the first round.
|2022 - seed 84
|(5) Jack Garland
|406 - 827