Los Tirasol Mentir was a male Alonis starfleet officer serving in the late 23rd and early 24th centuries. In 2311, he held the rank of Admiral. He was the second Alonis to ever join starfleet, and his application was sponsored by John "Blackjack" Harriman. Like all Alonis, Mentir enjoyed swimming and would often do so to release stress.

Mentir first met Blackjack in 2254 when the USS Allegiance arrived at Alonis on a diplomatic mission. Mentir enjoyed Blackjack's straightforward nature and the two became close friends.

Mentir taught at Starfleet Academy at one point and once instructed Demora Sulu in a xenoculture course.

In 2311, Mentir was forced to take over Blackjack's position in the covert plan surrounding the Tomed Incident after Blackjack was critically injured aboard the USS Ad Astra. He recruited Demora Sulu to recover three special operations operatives after the destruction of the IRW Tomed. (TLE novel: Serpents Among the Ruins)