Maximo Alisaunder Arrunja was a male Human Starfleet security officer who served aboard the USS Enterprise in the late 23rd century. He was past middle-aged, with grey hair, and had a talent for being unnoticed.
Arrunja was well suited to a job in security, as he had the capability to blend into crowds and not be noticed, but he was still able to present a dangerous aura which warned many of his charges. In an alternate 2270, Arrunja was charged with taking care of Dr. Georges Mordreaux after he was brought aboard the Enterprise from Aleph Prime. (TOS novel: The Entropy Effect)
In early 2285, Arrunja was a Lieutenant commander, and beamed down to Gateway with Chief of Security Beranardi al Auriga and Snnanagfashtalli in order to return Spock to the USS Enterprise. (TOS novel: Time for Yesterday) Later that year, he was serving as the chief of security aboard the Enterprise simulation for the Kobayashi Maru scenario test at Starfleet Academy. During the simulation, Lieutenant Saavik contacted Arrunja and informed him that he and a security team would possibly have to board the stricken SS Kobayashi Maru and aid its crew. (TOS novelization: Star Trek II: The Wrath of Khan)