Khata'n Zshaar was the captain of an Arkonian military vessel.
In 2152, Enterprise NX-01 was looking for Commander Tucker, who had crashed in a nearby system annexed by the Arkonians. Zshaar hailed Enterprise and ordered it to leave the system.
Captain Jonathan Archer told Zshaar that he would not leave until Tucker was found. Zshaar stated that one of his crew was also missing, and may have fired on Tucker. He agreed to work together with Archer to find the missing crewmen. Despite Vulcans perceiving Arkonians as being difficult to work with, as noted by T'Pol, Archer managed to establish a good working relationship with Zshaar and both of their lost men were retrieved.
Once both men were rescued, Khata'n Zshaar visited Enterprise to retrieve his man, and bid Archer farewell. He wasn't overly friendly towards Archer, but both showed a mutual respect. This first contact was more successful than that of the Vulcans in establishing relations with the Arkonians. (ENT: "Dawn")