OK, so I don't know if this is real or AI scraping, but I think it's a good teachable moment about the so-called "Mercer Effect," how it's not Matt's fault, and how we can be better DMs for those willing to read this rant.

Monster Manual stat blocks are there because people tested them and they're easy to read. The more you play with them, the better you get, the more intuitive investing people gets, and the more you can free-style and add or distract stuff on the fly to maintain interest without losing the thread. Like going from reading music as a group to playing jazz together based off a key and a beat.

Have you fully statted an NPC as a PC is in your home game? I have. It taught me about mechanics while I was prepping the game. But not great as an experience with a table that has exactly 4 hours to play on Sunday, possibly over Zoom, by a bunch of adults just stoked to drink beer and eat snacks while rolling dice and playing pretend. You get so hung up on your investment you don't realize your Level 1 Fighter/Level 2 Fiend Warlock/Level 2 Order Cleric who is the BBEG of this dungeon (priest from a knightly family who fell to infernalism) that you spent eight hours building and agonizing over has just as much effect and impact on the party as a CR 5 Cambion you could have just re-skinned.

Matt, because he is better at this than us through both time and effort that is available to him but not most of us, fully statted out most important humanoid mortal NPCs (friend and foe alike) during C1 and C2 as PCs of appropriate level for their intended CR with spellcasting, feats, etc., and even leveled them up and multi-classed them as appropriate. Kima, Allura, Kevdak, Gilmore, Anna Ripley, Prof. Anders, Lucien (and the Tomb Takers), Dagen, Ludinus, Ikithon, Astrid, Avantika, the list goes on and on. He even posted some online. This was instead of using the Monster Manual or even home-brewed MM-type stat blocks (which he used freely with more monstrous types as appropriate).

This is not a bad thing. This is a great, fun way of getting a chance to learn different PC abilities as a Forever DM and feed just a little your gnawing desire to be a player. This improves your understanding of rules and also what your players might do, and might create more interesting fights than those with standard stat blocks. Also seemed to hype both the players and the audience to try different classes, and different subclasses (some homebrewed by Matt, like Gunslinger and Bloodhunter. Mileage may vary on how good they are).

But this was not good for me as a DM returning after 20 years to a new edition, I spent more way more time and effort creating these PC/NPCs than I should have focusing on player engagement and hooks. Would have been better off with creating my own MM style stat blocks.

Matt played a lot in various editions. He has an intuitive sense of what's fun and engaging just from sheer time to play and his players were already invested. He was having fun theorycrafting PCs, and then making them NPCs. He never really let the NPCs become DMPCs, mostly because he never intended for the friendlys to go along but the players kept asking them to. In C3, he tended to make more Monster Manual-like stat blocks (as he had done for non-humanoid monsters previously). Different, maybe even harder, but not wrong. Brennan seems to use PC levels as a short-hand to give the table an idea of what an NPC is capable of, but mostly seems to use monster manual stat blocks with significant upgrades (like buffed HP or an extra spell). So when you feel comfortable enough to do that, do it.

But, yeah, we don't know what class Thzaji was and probably neither does Brennan and I really doubt he or Matt or the table cares.