Mainboard (60)
Creatures (33)
Instants (5)
Sorceries (3)
Enchantments (4)
Boros Energy is fast and aggressive, so your Living End cascade must land before they can kill you; Teferi, Time Raveler stops Solitude and instant-speed exile effects, while also making your Living End uncounterable by bouncing their flash interaction. Mystical Dispute counters their key spells at nearly free since Ragavan, Guide of Souls, and Ocelot Pride are all red or white. Commandeer is too conditional against their mostly low-cost threats; Striped Riverwinder and Colossal Skyturtle are expensive bodies that don't accelerate your combo. Endurance in your main deck allows you to reset your graveyard after their Goblin Bombardment eats your cyclers, and Clarion Conqueror post-Living End can dominate the board.
Jeskai Blink is heavily interactive with Solitude, Consign to Memory, and Teferi that can bounce Living End; your Teferi, Time Raveler is essential to make Living End uncounterable at sorcery speed while shutting off their flash exile. Mystical Dispute counters Solitude, Consign to Memory, and Quantum Riddler at a steep discount as their entire deck is blue or white. Clarion Conqueror post-Living End is the trump card since Jeskai has limited ability to deal with hasty flying threats. Waker of Waves and Striped Riverwinder are slow cyclers that don't pressure the combo window efficiently. Ardent Plea in the main deck needs protection, making Teferi critical.
Affinity brings in Grafdigger's Cage and Tormod's Crypt to prevent your Living End from working, making Force of Vigor and Foundation Breaker critical to destroy those graveyard hate pieces before you cascade. Mystical Dispute counters Kappa Cannoneer or Weapons Manufacturing at a discount since most Affinity payoffs are blue. Commandeer is too conditional; Waker of Waves and Sink into Stupor are slow cycle outlets that don't address the hate they board in. You must clear their Grafdigger's Cage or Tormod's Crypt before attempting the Living End cascade — prioritize finding Force of Vigor or Foundation Breaker with your free spells.