Two words from me. I didn't play a lot with this nation, but it's got plenty to offer.
I hate bless strats - lame...
Myslef I like go blood and damn expensive but still deadly devils spamming through 'soul contracts' (each 65 blood slaves and 5F gems). Some imps summoning to get devils some support against massed armies & priests casting banishing. You can mix all of that with those national demonic flyers. This can work fine in larger games, with more provinces wich are harder to defend.
As a pretender - Blood Fountain, high dominion, great scales with no death, magic 3.
Smaller games I'd recommend salamandeders mixed with shieldless axe guys on your wings, trying to flank the enemy with speed 7
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Middle field with shielded gus, cheap mage support with fireball (my favourite spell here).
Both kind of games, I'm allways searching for fire magic sites using spells - fire gems are pure gold wich is never too much.
I do not concentrate on fire summons, blood path provides them.
But going back to blood eco - this is the most difficult part... but you've got strong flyers to patrol and lots of gold to afford it.
Just two words from me, as I'm bored at work - I'll edit that as I'm back home, maybe with some more details and less chaos
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