This is a race between two combo decks — Tireless Tribe aims to assemble Tireless Tribe plus Inside Out lethal damage on turn 3-4, protecting their creature with Loran's Escape and Prismatic Strands. Cast Down is the most critical card post-board, cleanly answering Tireless Tribe at instant speed before they can attack, while the two additional Mesmeric Fiends let us rip Inside Out or protection spells from their hand before they combo off. Flaring Pain is included because Prismatic Strands can legally prevent the non-combat damage Lotleth Giant deals via its enter-the-battlefield trigger, and a single copy blanks that line entirely. Masked Vandal is trimmed since their deck runs almost no relevant artifact or enchantment targets, and Quirion Ranger and Troll of Khazad-dum are cut as the slowest non-combo pieces to make room for the disruption we need to win the race.