UR Aggro is your fastest matchup — Outcaster Trailblazer and Spider Manifestation can apply lethal pressure before you assemble Omniscience, so you need early interaction. Fire Magic comes in as clean removal for their key threats, particularly early creatures like Llanowar Elves and Spider Manifestation. Spider-Sense provides countermagic to protect your combo pieces and disrupt their high-impact instant and sorcery spells. Winternight Stories and Prismari Charm are trimmed because they are too slow or too low-impact to matter in a race where you need to survive to the mid-game. Post-board, be aware they bring in Ill-Timed Explosion, so prioritize landing a protected Omniscience over developing a board presence that gets swept.