Lokai was a native of the planet Cheron. He was half white and half black, with a dividing line which ran down the middle of his body. He explained that his people were oppressed on Cheron because of their color. The ruling class on Cheron were also black and white, but were black on the right side not the left side like Lokai's people. He possessed a personal force field which protected him from phaser fire and block any attempt at unwanted physical contact.
Approximately 50,000 years before 2268, Lokai was a leader in a revolution. After his capture, he was tried and convicted of treason by the Commission on Political Traitors. Lokai escaped, with Bele in pursuit.
In 2268, Lokai requested asylum on board the USS Enterprise after stealing the Federation shuttlecraft da Vinci from Starbase 4. Lokai was not that familiar with Federation law and policies, going so far as to misspeak the name of the Federation as the United Fleet of Planets.
Nevertheless, Lokai put his trust in Captain James T. Kirk since Lokai was at the time being pursued by Bele, who had chased him for over 50,000 years and wanted to return Lokai to Cheron for judgement.
Lokai was refused asylum on the Enterprise. Captain Kirk then received orders to take him to the nearest starbase to face charges followed by a hearing with Starfleet Command to determine his asylum status. Kirk also refused to turn him over to Bele and return them to Cheron. Bele was outraged and said that Lokai had "gained allies even if they did not recognize themselves as being such".
After the Enterprise decontamination mission to the planet Ariannus was completed, Bele gained control of the ship, and headed for Cheron. Upon arrival, Lokai discovered that the entire population of Cheron had annihilated itself in civil war. Kirk offered Lokai a chance to live with the Federation. Lokai refused and beamed down to the dead planet with Bele in pursuit. (TOS: "Let That Be Your Last Battlefield")