Alfren Cheno served as a commander in the Imperial Navy as a human male in the years leading up to the Galactic Civil War. During the battle over Umbara, he was in command of the Thunder Wasp, working alongside his first officer, Captain Thrawn. Cheno, along with the crew of the Thunder Wasp, successfully shifted the battle's momentum with Thrawn's assistance, despite the orders coming from Admiral Carlou Gendling. As a result of Gendling's feelings of inadequacy related to the battle, Cheno was compelled to retire.
Sometime later, Moff Haveland shared with Grand Admiral Balanhai Savit whispers suggesting that Thrawn's numerous accomplishments were due to a clandestine advisor. Haveland suggested Commander Cheno as a potential candidate for that advisor, but Savit immediately rejected this idea.
Wullf Yularen considered Cheno to be a competent officer, but not exceptional, and Cheno himself admitted to being only an "adequate officer." He possessed a strong understanding of his own shortcomings as a commander and showed a kind and approachable demeanor towards his subordinates. However, in contrast to the majority of officers in the navy, he possessed the insight to acknowledge Thrawn's extraordinary talent and the humility to openly appreciate and support him. Ultimately, he prioritized the needs of the navy over his own ambitions, sacrificing his career to protect Thrawn.