Co-op in Starcraft II is divided into two modes: Multiplayer "comp stomp" against A.I. bots, and the Co-Op Missions. As of November 14, 2017, all of the co-op can be played for free without purchasing any of the campaigns, with one caveat (noted below) for the Co-Op Missions.
Custom Matches (i.e., Multiplayer Comp Stomp): Up to four players can join up online or via LAN (or a mix) in a team battle against A.I. opponents. Each player controls and manages their own army. Players can also work together and control the same army against A.I. opponents in Archon Mode. These options can be found under the "Custom" tab in-game. The "Arcade" mode allows for user submitted maps/creations, which may support up to eight players total.
Co-Op Missions: Up to two players, online or via LAN, can team up to take on special co-op missions. These missions differ from the usual base-building and squadron combat in the main campaign and multiplayer modes. Prior to starting a co-op missions, each player selects a commander to use. Each commander has unique abilities and particular units to which they have access. As you play matches, the commanders gain levels, providing access to new units and abilities. Now that Starcraft II is free-to-play, all players will have access to Raynor, Kerrigan, and Artanis, and be able to level them to the max level of 15. Players will have access to all the other Co-Op Commanders, too, but those commanders are capped at level 5. Commanders can be unlocked individually for $5 each.
Welcome to the Koprulu sector. You are Jim Raynor, and you're on a crusade to bring down the Dominion and its nefarious leader, Arcturus Mengsk. Haunted by betrayal and remorse, some believe you've given up the fight. But you have promises to keep – and a need for vengeance that’s long overdue.
Starcraft II takes place four years after the events of StarCraft: Brood War. There are three campaigns total you can play through that are focused on each of the three playable races: terran (Wings of Liberty, free), zerg (Heart of the Swarm), and protoss (Legacy of the Void).
This page contains co-op info for Starcraft II on the PC. All information about Starcraft II was correct at the time of posting. Information is subject to change. If you see any errors please email us.