Devoted Combo wants to resolve Devoted Druid plus Vizier of Remedies to generate infinite green mana, or Badgermole Cub and mana dorks to ramp out a huge amount of green mana, then dump it into Craterhoof Behemoth or Ouroboroid; Brotherhood's End's 3 damage sweeps their one- and two-toughness dorks (Delighted Halfling, Devoted Druid, Birds of Paradise, Badgermole Cub) before the engine comes online, though it also hits your own creatures and planeswalkers, so be careful with Wrenn and Six and your Fable of the Mirror-Breaker token. Boseiju, Who Endures answers Leyline of Abundance or Agatha's Soul Cauldron, and Consign to Memory can counter the Craterhoof Behemoth or Ouroboroid triggers, as well as colorless spells like Walking Ballista. High Noon and Kaya's Guile are too slow and don't interact with the actual mana engine, so they're the cuts. Keep Galvanic Discharge and Leyline Binding up to snipe key dorks like Devoted Druid or Vizier of Remedies on sight.