I saw another post mentioning the origins of the Moritat death cult being explained in the RH? Does anyone mind explaining it to me in detail either via response or PM? It's a background package I've used numerous times and thus would like any knowledge on them I can gain.

Yep, it does cover some of the stuff about the Moritat. However, it takes up several pages, so it can't really be reproduced here. Best bet is to buy the book

Is it a single section or strewn throughout the book? Because I at least haven't found too much mentioning of them when skimming through the book. Mind giving a page number? I'd really like to read more about everyone's favorite sushi chefs.

Well, the entire first fiction for a start, that's over several pages.

Yeap, introduction of the first chapter features several story-linked reports and transcripts, whose main character is mind-cleansed Moritat assasin (at the end, even whole Moritat Extermination Cell). Plus at the end, there´s exorcised Moritat character which was also featured in Design Diaries IIRC- Seraph. And that´s all I think.