Flamedancers, ice demons, occultists as support.
Heroes – Drakarot (+10 dmg to all!), Gul’ras and probably Brakarash or Dark focus (R5 BWT hero).
Generic artifacts from story, optional: some hellfire sparks (+3 fire dmg).
Mass +3 air damage instruments.
2-3 Ancestor’s armors.
(optional) 300-600 BWT
110 R3 boss tokens
~450 yellow R4 tokens (you’ll get plenty if you’ll try to farm ice daggers for infantry).
Few weeks of ice demons farm (you’ll get some R5 tokens in the process though)
100+ yellow R2 tokens (you’ll most likely have plenty of leftovers in R2)
Army strength: ~10k
Mission requirements: 5.3 completed
Strength: Different damage types, only spellcasters in build (many procs are ignored), splash damage from fire rain and hailstorm.
Weaknesses: Fear (as most of the spellcasters builds :/ ), water damage to elites, mass weakness/damage prevention.
To get rid of some of these you can use one bombrunner to disable one-two enemy units/give 10 water damage resistance to your army.