This thread proves that people are either skim reading the manga or cannot read
King of Hell is when Zoro lets Enma take as much Haki as it wants and keeping that drain consistent, basically he is allowing Enma free reign
It sucks out so much (pause) Haki that it also pulls out Zoro's Conqueror's Haki
That's it, that's all King of Hell is
King of Hell is when Zoro outputs massive amounts of Haki to meet Enma's demands
Zoro is not aware that he has Conqueror's Haki and probably thinks all Enma draws out if Armament Haki
What he's doing now is drawing out Conqueror's Haki on his own, with his own control over it, how he coats it, the output, etc. without relying on Enma