Bloodmage Thalnos is one of the most fun heroes to play in Warcraft Rumble. The hero's passive ability grants a level-up every time you cast a spell. For that reason, we'll be utilizing three spells in the deck. Thalnos also needs to survive, so a strong tank and a supporting unit is a must, and we get that with Abomination and Shaman. If you can get Thalnos +10 levels (the cap), the Lifesteal ability will ensure you can defeat any PvE encounter!
Abomination: Thalnos needs to survive, and Abomination is the toughest tank in the game. Have him lead the charge and let Thalnos do the work at range. Lifesteal is a must, as this will allow Thalnos to survive and fight bosses head-to-head.
Ghoul: Not an essential unit, but it's a solid low-cost Undead option for our deck, and at 2-cost, it's probably the best options, but feel free to experiment!
Blizzard: Spells grant Thalnos a level, so you can use Blizzard or Holy Nova here. Frost Snap is a solid skill for Blizzard as it freezes enemies in place.
Frostwolf Shaman: The support unit. Earth Shield is a must, as it will allow Abomination and Thalnos to survive longer.
Chain Lightning: Another spell to grant Thalnos levels. Brilliant Flash is nice because it stuns enemies, but it is in no way required.
Arcane Blast: Another spell for our deck. Amplification is nice here but not required.