In Utter Darkness

This is the Protoss's final stand against the Zerg invasion. It's impossible to destroy the Zerg outright, so your only option is to hold out and destroy as many as possible. You'll need to kill of 1,500 Zerg to count towards a victory. Besides Zeratul, you'll be aided by Urun and his phoenix, Mohandar in a custom void ray, Selendis is a carrier, and Artnais will bring a mothership.

There are three different choke points into your base, all on opposite sides. You'll want to divide your forces equally and place them to guard these entrances. Your photon cannons will also be hit with constant assaults, so be ready to have a probe warp in backups. Nydus worms will also attack the center of your base, so be sure to keep some defense there as well.

Keep producing probes to gather resources and warp in units to replace your fallen ones. With a continual supply of stargates and gateways sending in allies, you'll be able to destroy 1,500 Zerg in no time. After the initial 1,500 are dealt with, the Zerg will push even harder. Continue to fight as many as possible. The mission will conclude once all of your forces are obliterated.