Seth is the main antagonist and final boss of Street Fighter IV. He is a formidable opponent known for his unique ability to mimic special moves from other characters, his high damage output, and his aggressive, unpredictable AI. Defeating Seth is often considered the ultimate challenge of Arcade Mode.

Seth's Signature Moves:
- Tanden Engine (Vortex): Seth's most iconic move. He creates a vortex that pulls the opponent in, dealing multiple hits. This move often leads to his most damaging combos.
- Shoryuken (Uppercut): Seth has a very fast and damaging Shoryuken, often used as an anti-air or reversal.
- Sonic Boom (Projectile): He can throw fast Sonic Booms, sometimes in quick succession, to control space.
- Spinning Piledriver (Command Grab): If you get too close, Seth can execute a powerful command grab that deals massive damage.
- Yoga Teleport (Teleport): Seth can instantly teleport behind or in front of you, making him difficult to corner or predict.
- Ultra Combo (Tanden Stream): A full-screen, multi-hit attack that is incredibly damaging.
Strategy & Weaknesses:
- Maintain Mid-Range: Avoid being too close (to prevent SPD) or too far (to avoid Sonic Boom spam). The ideal range is just outside his normal attack range.
- Anti-Air Reliably: Seth jumps frequently. Be prepared to anti-air him with your character's most consistent anti-air move (e.g., Shoryuken, Flash Kick).
- Block Tanden Engine: When Seth activates Tanden Engine, block it. If you get caught, try to block the subsequent hits. Do not try to mash out, as you'll likely take more damage.
- Punish Whiffs: Seth will occasionally whiff a Shoryuken or other unsafe moves. These are your prime opportunities to dash in and land your most damaging combo.
- Focus Attack Counter: A well-timed charged Focus Attack can absorb one of Seth's hits and crumple him, leaving him open for a free combo or Ultra.
- Ultra Combo Usage: Save your Ultra Combo for when Seth is clearly vulnerable, such as after a blocked Tanden Engine or a whiffed attack. Do not use it if there's a chance he'll block.
- Patience and Defense: Seth is a test of patience. Don't rush in recklessly. Play defensively, block his strings, and look for small openings to chip away at his health.
- Corner Pressure: If you can get Seth into the corner, apply pressure with safe strings and mix-ups, but be wary of his Shoryuken and Teleport.
Defeating Seth often requires multiple attempts. Learn his patterns, adapt your strategy, and focus on clean execution.