Hadn't checked this thread for a while...
I was Mictlan in this game, had a fire 9 moloch as my pretender, and the blessing worked out quite nicely as a expansion tool in the beginning. I made a bunch of Soul Contracts and concentrated on getting demon SCs after that. I made loads of mistakes, but hopefully learned something too.
I made an early alliance with Ulm, who supplied me with quite a few magic items and gems later on.
Around the same time I met Pangaea, who was just finishing his war with Marignon. I contemplated attacking him then, but decided against it, figuring I'd be better off developing a good blood economy before any wars.
Man and I started planning our war against Pangaea something like 30 turns before we attacked him, and I'm pretty sure that was a mistake. We waited too long.
I summoned all the Arch Devils, 1 Heliophagus, and a bunch of succubi, and started stocking up on slaves for Send Horror and Hordes From Hell, and made loads of Blood booster items. Major mistake, should've gotten all the SC-type demons I could.
When the war started I spread my forces too thin, spending too much effort on taking all of Pangaeas provinces & too little on dealing with his armies. I underestimated the effectiveness of Lamias and Iron Dragons, and managed to get too many of my SCs and devils killed, particularly in an attempt to rout-kill Abysia's IDs, which failed miserably.
After a series of defeats I finally wised up and consolidated my forces and managed to defeat Pangaea's big invading army, though probably this turn in the tide would've been only temporary had the game Lasted longer.