In The Dark is a StarCraft II short story written by David Gerrold, designed to tie-in with Heart of the Swarm. It focuses on the dark templar. The story was later collected in StarCraft II: War Stories.
A runaway Terran soldier finds a mysterious and exotic planet to start a new life by himself. He meets an enigmatic Dark Templar who seeks to destroy a strange breed of Zerg on the planet.
Between the two Great Wars, Jake, a former Terran Dominion colony supply pilot, went AWOL after his service was extended. He had spent years scanning the various planets to find a place he could be left alone, as Jake had his mind damaged by a telepath during a transport operation years earlier that made it so the psychic "noise" that came from other humans caused him pain. During a battle he forced his colony ship to evacuate, then sped away with the ship to a planet he had discovered with optimal conditions.
Upon arriving, he named this planet Goldilocks, and set his adjutant to scanning the planet for the most optimal spot to live. He found it on a large island off of the main continent, and after some trepidation sent down colony supplies and sped down to the surface. He set up a camp at the base of a large volcano, with flow water coming down from the icy peaks of it. Late one night, Jake heard a screeching scream that echoed even psychically through his damaged mind. He sent probes out, and spent six days searching the island on his vulture, but could not find the source.
During one of his trips to explore the island, Jake was realized a super-storm was on the horizon, and he wouldn't make it back to camp in time. He sped toward one of the lava tubes, massive caves in the side of the volcano, and used it to cover himself until the storm passed. Upon getting far into the cave, he landed his vulture, took what weapons he could, and explored.
After marveling at the formations made from the lava flows, Jake discovered a piece of protoss machinery in the caverns, damaged by claw marks. Disheartened that he wasn't able to escape from the major powers of the sector, Jake continued to look further. He found the remains of stalker and immortal frames, leading him to believe that a battle had occurred in the volcano. He tried to scout the room with micro-spies, but a flash destroyed them all, and a figure appeared. Jake stood face to face with a protoss dark templar, Lassatar.
Lassatar considered the human, and thought back to humanity's place in the grand cosmic scale. Earlier he had been sent to find a xel'naga relic relic, but encountered a human child that showed him there was a side deeper to humanity then their primal urges. He took the artifact to an abandoned asteroid, then discovered its ability to enhance psionic potential. Upon taking it back to the acolytes who studied it, they took it and fled to Goldilocks. Lassatar had followed them here. He found the acolytes dead, having tried to uplift the zerg into something less violent but having failed.
Lassatar decided to spare the human, seeing no need to wastefully take life, then vanished into the shadows. Fearing the meaning behind the protoss presence on this world, Jake decided that the only solution was to further explore. Meanwhile, Lassatar set on destroying the zerg colony here before it could be assimilated into the main body of the Swarm. Jake meanwhile ran into a room with zerg creep, then ran. Zerg bioforms perused him, and he fired back, killing a good number of zerglings. However, they kept swarming, and Jake was running out of ammo. Desperate, Jake collapsed the top of one of the tunnels to cut him off from the zerg.
A larger, mutated ultralisk broke through to him, stunning Jake. Just then, Lassatar appeared and slew the ultralisk, using the power of the artifact. He discovered it was a psionic lens, amplifying his power, as well as something more. Jake killed some zerg behind Lassatar, and the protoss raised his hand in a gesture before vanishing. Jake realized that meant he may have wanted something from Jake, then he got back on his vulture, and made for his base camp, the storm having mostly passed.
Lassatar then used the psionic lens to imprint the image of every inch of the volcanic tubes into Jakes mind, showing him where to trigger the volcano and destroy the nest of zerg there. Jake was upset, but the psychic influence of Lassatar gave him the overwhelming need to destroy the nest. He ran simulations in his puddlejumper, and gathered what explosives he could to trigger the volcano. He would use MULEs to drill into the volcano, then put liquid explosives in the holes, detonating them and causing an eruption.
Jake set his MULEs to work, while Lassatar left behind what protoss technology he could to distract the zerg. A zergling discovered the MULE, and brought the experience back to the hive cluster. Amplified by the psionic lens, the zerg began experiencing panic, and the hive cluster began to destabilize. The volcano erupted, destroying everything inside. Jake and Lassatar met for the last time, then the protoss vanished. Jake realized he now had to leave, this time to a place with other humans.
Gerrold, David. "In The Dark." (May 02, 2013). Blizzard Entertainment. StarCraft Lore: In The Dark Accessed 2013-05-02.