Tasari was a Fabrini male who served as a bodyguard for High Priestess Natira on the generational asteroid ship Yonada during the final years of its journey to the Promised World Lorina.
When the USS Enterprise detected the Yonada, a landing party consisting of Captain Kirk, Mr. Spock, and Dr. McCoy beamed aboard the ship. After a few minutes the tubes on the surface opened and the landing party was attacked by several Fabrini guards, including Tasari. When McCoy briefly froze upon seeing Natira for the first time, Tasari hit McCoy in the back of his head with the pommel of his sword.
The crew of the Enterprise was later able to override the Oracle that ruled over Yonada, correcting the course of the ship to prevent a collision with Daran V. (TOS episode: "For the World is Hollow and I Have Touched the Sky")
In the aftermath of this, the instruments of obedience were removed from the Fabrini, and the Federation assisted the Yonadi in establishing a colony on Daran IV, which they named Lorina. Tasari remained as Minister of Security in Natira's government.
However the actions of the Enterprise and the Federation were controversial amongst the colonists. This resulted in violence against the government and the Lorini who supported them. As Minister of Security Tasari was quick to crack down on any rebellion, using harsh methods against the populace. Tasari's troops came to be seen as thugs who only worked to silence Natira's enemies. As a result more extreme elements in Lorina society committed a series of terrorist attacks.
After Tasari attempt to arrest High Priestess Rishala sparked a riot with a large number of civilian casualties, Captain Kirk convinced both Rishala and Natira to convene peace talks to work out their differences.
Tasari was part of Governess Natira's delegation in peace talks spearheaded by Captain Kirk and held on Yonada. These talks were disrupted by the Lorini terrorist Dovraku and his followers. Tasari and several others were taken hostage, and taken to the Oracle temple complex. There the Oracle was reprogrammed by Dovraku to do his bidding, and upon being reactivated Dovraku was quick to have the Oracle murder Tasari.
The situation was soon resolved by Mr. Spock, who forced Dovraku to confront his personal demons, leaving the man in a catatonic state. With both Dovraku and Tasari out of the picture and a renewed commitment to making the colony work from both Natira and the Lorini dissidents the violence quickly died down. (TOS novel: Ex Machina)