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What advice could you give me to face SM Ultras? I have most anything available so feel free to suggest.
Just about anything that will ignore their saves.
Tyrant, Broodlord, Lictor, rending warriors, rending raveners, genestealers, canifex and zoanthropes will a cause damage, plus serious damage if the get to their lines, if you hit him with enough attacks he will fail them.