Obrist was a Krenim officer and second-in-command of the Krenim weapon ship. He had a brother, whom he had not seen since he joined Annorax in his mission to restore the Krenim Imperium two centuries ago. Obrist celebrated the birthdays of his brother, parents, and closest friends for a century, until he realized that as a consequence of their isolation from the timeline, those people were either dead or had never existed in the first place.
In 2374, Obrist tried to convince Annorax to dismantle the weapons ship after they achieved a 98% restoration with the erasure of the Zahl. Annorax refused, deepening Obrist's disillusionment towards their mission. After Annorax abducted Chakotay and Tom Paris from the USS Voyager, Obrist formed a friendship with Paris and told him about the crew's discontent. Obrist agreed to help Paris send a message to Voyager, in order to plan an attack. After the battle begun, Obrist took the ship's temporal core offline, rendering the weapons ship vulnerable to conventional weapons, and transported Chakotay and Paris off the ship. Obrist was returned to his old life when the original timeline was restored after the weapons ship erased itself from history. (VOY: "Year of Hell", "Year of Hell, Part II")