This is the mirror, so the game is decided by who assembles their combo first and who can disrupt the other; Thoughtseize is premium here to strip their Devoted Druid, Green Sun's Zenith, or a key piece of interaction like their own Fatal Push before they combo off. Drannith Magistrate doesn't stop their core combo (which is cast from hand) but does prevent them from casting Nature's Rhythm from the graveyard via Harmonize and can block their small creatures. Abrupt Decay provides uncounterable removal that can cleanly destroy an early Badgermole Cub. Fatal Push cannot destroy their bigger threats like Craterhoof Behemoth, so we trim it slightly in favor of proactive disruption.