Dalak is a Krill Captain who commands a Krill destroyer.Avis united our paths for a reason. But only he truly knows why. We shall see where that path leads.— Dalak to Captain Ed Mercer
Dalak's ship, flanked by two other Krill destroyers, captures the Union shuttlecraft ECV-197-1 via tractor beam when it enters Krill space. Taking aboard Commander Kelly Grayson and Lieutenant Gordon Malloy, Dalak receives them in his bridge. There, he is told of the Kaylon, who intend to wipe out all forms of biological life in the galaxy, beginning with an invasion of the Union capital of Earth. Pointing out that the Krill are under threat as well, Grayson and Malloy plead with Dalak to assemble the Krill fleet and take them back to Earth to join with the Union Fleet. Believing that the Union officers mean to lead his forces into an ambush, Dalak orders them to be taken to interrogation before being killed. Soon after, however, Kaylon Sphere 15 arrives in pursuit of the Union shuttle. A battle ensues between the Krill and the Kaylon, with Dalak's ship only managing to destroy the Sphere after losing his sister ships.
Convinced of the Kaylon threat, Dalak assembles a fleet of dozens of Krill destroyers and sets a course for Earth. Arriving in Earth's solar system, the Krill promptly join the fight against the Kaylon. Dalak makes contact with his guests' ship, the USS Orville. Introduced to Captain Ed Mercer by Commander Grayson, Dalak tells him to stay out of his way. Dalak orders all destroyers to launch their Marauder-class fighters, allowing one of his own to be piloted by Lieutenant Malloy. Though both the Union and the Krill take heavy losses, Dalak's ship survives and sees that what is left of the Kaylon forces retreat to their home planet. The battle over, Dalak hails Mercer again, assuring him that he can send a shuttle to pick up his crewmen. When Mercer voices his hope that the Union and the Krill may find common ground in light of their mutual enemy, Dalak observes that Avis united their peoples' paths for a reason that only he knows, and that they will see where it leads them. Ultimately, the surviving Krill vessels return to their own space.
As is typical of Krill, Dalak is fiercely devoted to their god, Avis. He looked down particularly upon humans, regarding them as a "godless race of sub-creatures well-trained to lie and deceive." However, his perspective is changed following the Battle of Earth.
- Dalak shares his name with the Daleks, a xenophobic race of cyborg warriors and longest-standing antagonists in the British science-fiction series Doctor Who, who bear similarities to both the Krill and the Kaylon. However, his name is pronounced DAY-LEK rather than DAH-LEK.