Guardian of the Guildpact is the central problem here — its protection from monocolored means Snuff Out and Cast Down are blanks against it, so Arms of Hadar is essential as a non-targeting sweeper that kills Guardian alongside their low-toughness support creatures like Sacred Cat and Outlaw Medic. Prioritize Counterspell and Spellstutter Sprite on Armadillo Cloak above all else, as an enchanted Guardian or even an Outlaw Medic becomes nearly unbeatable with their lifegain engine running. Unexpected Fangs on a Spellstutter Sprite or Sneaky Snacker lets you contest the life total race directly, turning their Armadillo Cloak clock into a two-way race. Thorn of the Black Rose comes out because they attack freely on the ground with multiple creatures and will steal the monarch immediately; Gurmag Angler is too slow and too easily blanked by Prismatic Strands when they're padding their life total each turn.