The Technocrat
Collect tracking devices by defeating Vex in Asterion Abyss. Minotaurs will always drop the devices.
Variks informs you that Praksis's latest experiment involves the Vex. He attached a tracking device to some of them. By retrieving those tracking devices, you should get a lead on his location.
"Praksis admires the Vex. He seeks to use them to improve Eliksni technology. Variks does not know how." —Variks the Loyal