The Axanar had green blood. Their bodies produced triglobulin from the zymuth gland. This substance had medical and aphrodisiac properties, and was used by a number of different species for those purposes. Some even forcefully "harvest" Axanar for their triglobulin.
In 2151, Humans made first contact with the Axanar via Enterprise NX-01, when an unnamed species had attacked one of their freighters. Enterprise sent an away team over to investigate, and found the mutilated corpses of the crew. When the Axanar returned, responding to a distress signal set by the Enterprise crew, a translator malfunction led them to believe that Enterprise itself was responsible. Fortunately, Hoshi Sato, having translated the Axanar language, was able to convey to the Axanar that the true attackers were the ones attacking Enterprise, to which the Axanar offered assistance. (ENT: "Fight or Flight")
Sometime prior to 2152, an Axanar starship stopped by the automated repair station. One of the Axanar crewmen was secretly added to the station's humanoid hosts whose brains had been tied to the computer of the station. (ENT: "Dead Stop")
By the mid-23rd century, a conflict had broken out at the site of the Axanar's homeworld, involving the United Federation of Planets, Starfleet, and Captain Garth of Izar. Garth was victorious in what became known as the Battle of Axanar and his exploits in the action became required reading at Starfleet Academy. James T. Kirk participated in the subsequent peace mission at Axanar, for which he was awarded the Palm Leaf of Axanar Peace Mission. (TOS: "Court Martial", "Whom Gods Destroy")
- There have been no named Axanar in canon.