Multiple realities(covers information from several alternate timelines)
Alnschloss K'Bentayr was an officer on the USS Kelvin in 2233.
When the ship was attacked by the Romulan mining vessel Narada, creating the alternate reality, Alnschloss left the bridge and abandoned ship along with the rest of the crew. (Star Trek)
In 2259, another member of Alnschloss' species was serving aboard the USS Enterprise. (Star Trek Into Darkness)
Alnschloss K'Bentayr was portrayed by actress Katarzyna Kowalczyk.
Alnschloss' appearance was based on a design by Neville Page. 
Alnschloss' name comes from production sources and was never mentioned on-screen - and neither was its gender. According to the viral site Starfleet Shipyard, Alnschloss was born on the planet Monchezke in the Beta Quadrant, and its service number was SA-890-0404-DB and was the security officer. The virtual collectible card battle game Star Trek: Rivals has a card, #5 Security Officer A. K'Bentayr.
In Issue 14 of IDW Publishing's Star Trek: Ongoing series, K'Bentayr is present when Captain Richard Robau and Lieutenant commander George Kirk made first contact with the Roylans.
A cadet named Vel K'Bentayr (likely a relative) is featured in the 2015 Starfleet Academy comics by IDW.