My pretender was a Dormant Man-Eater with full scales and no bless. At some point it gave me access to Blood: I summoned Father Illearth and empowered scouts for blood hunting. In late game I was summoning Heliophagus, vampires, etc. Overall PEACENIK served me well. For Dom5, the new summons and the changes to luck might inform future designs.
I started expanding on turn 2 and managed to get all the mercenaries. I also got thousands of gold in events early on, fueling an elephant+mercenaries expansion. The first province I conquered had sages (no need for search) and I started hiring them nonstop, ensuring steep research curves from the beginning (according to my notes, at turn 28 I had thaumaturgy 5, conjuration 4, construction 6, evocation 6, about 1K RP/month...). By the start of the second year, I had 26 provinces, 2 forts, and I had surrounded a large number of independent provinces on my North. I reached 34 provinces on turn 19 but only 38 (about my max) on turn 34. Clearly, this expansion was gold, but I managed to waste it by my lack of talent at battlemagic in mid- and late game.
I started aggressing Ermor on turn 23 (by this time I had 5 forts, 6 mage-producing provinces). My goal was really to get rid of the undead; I had just lost a game to them as Ashdod and I did not want my last Dom4 game to repeat the pattern. At the same time, I did not fully commit to this war, even though I could probably have emptied my Eastern holdings of their garrisons thanks to a lasting peace with my neighbours. T'ien Ch'i going AI was bad news and something I did not understand as a player.
Ermor was a formidable and skilled opponent, first on the battlefied and then with assymetrical warfare (bane venom charm carriers, at some point I had 80+ afflictions healed/month). Fun fact: Ermor AI died in turn 70 something.
There were wars elsewhere I was not involved with, and my lowish or rather slowish commitment to the Ermorian war (building up big stacks) ensured that my overall losses were negligible, thus reinforcing my economic advance. I hired many priestesses and as a result my units were healthy and experienced. Two stars can change an average unit into an OK unit I think.
Hero Joe, my Prophet, was my start commander. Later on I empowered him in Blood so he could take part in communions and push his holy level to high levels (I got to H7 I think, he was also reinvingorating the mystic slaves). IIRC he died from Blood Vengeance. I resurrected him as a Mummy. My advice for Arco would be to Prophetize mystics (provided the communion raise in H levels still functions in Dom5).
Ulm and I, both neighbours of Ermor, allied early on. I conceded the Throne between us and we traded a little bit. C'tis was an enigma all game long, staying mostly to itself. Marignon was a distant partner but had I managed to stay in the T'ien Ch'i region longer I feel he might have attacked me, instead there was a war brewing between him and Ulm. Bandar Log was in a bad starting position and, after some time, we got into a secret alliance because I did not want him to be invaded by Agartha or Oceania. I funnelled thousands of gold and hundreds of gems and slaves to him.
Oceania was a bit of a mystery, even less involved in the war against Ermor and only launching what appeared to be short-lived token assaults on the undead. I suspected a secret alliance between him and Ermor, though who knows.
My feeling was that Agartha was the other big player. In my test game Agartha AI had won the day and scooped the Thrones. It took me some time to understand that all the graphically underground provinces were not necessarily cave provinces.
I started crafting artifacts at the end of the third year and did not stop until a couple of turns ago. I was complacent and had no focused strategy, instead trying to grab everything (royals, etc.). When Oceania, already the owners of Mother Oak and Gift of Health, cast Gift of Nature's Bounty and Arcane Nexus, I felt I had no choice but to commit everything to the conflict for the globals. I was 4 turns away from being able to cast my own Arcane Nexus, so I started by dispelling the Oceania one with moderate overcasting (I don't remember the overcast number, but it was not much). Then Oceania re-cast it and by that time I was able to snatch it. I also gave the gems to Bandar Log for the nature globals, and loaned him boosters (he crafted me a precious Robe of the Magi). At this stage (turn ~69) Agartha was not like USSR in 1945 (an ally / frenemy) but more like USSR in a Tom Clancy novel (invaders!) so I cast Wrath of God and later Vengeful Water. I was a bit imprepared but really I should have cast Vengeful Water much earlier. Now I still have 3 good globals (I dispelled Wrath of God with my Vengeful Water cast) so I am in a good position on that front but Agartha took many forts from me. I would be fighting an uphill battle but my fundamentals are better I think: gem income (I have Atlas of Creation-ed most of my territory), growing vampire count and still decent gold income despite the Armageddon that Oceania cast (I believe to try to kill my global caster, but the poor dude is cocooned in protecting items and cannot escape monitoring by bodyguards even to take a dump), and last but not least a better understanding of the way I suck at using Golems in battles.
On turn 78, I am 3 turns away from completing research of all schools of magic, which would be pretty cool. Obviously if I had a more competitive mindset, I would have stopped researching some time ago to muster a couple of huge communions (32+ slaves each). It was always more simple to keep the rat labs on research though. Yes, communion scripting does take its toll. It's quite fun but the UX does not keep up when the communion scales up, and it becomes a bit tedious.
Thanks to all players for this interesting game, with a shoutout to the players who stuck to it as long as it made sense. I had lots of fun.