Kasrene was a Tholian who served as an ambassador in the 23rd century.
In 2298, she served as an envoy who meet Aidan Burgess along with the crew of the USS Excelsior during negotiations between the United Federation of Planets and the Tholian Assembly. However, during the meeting, it was thought by her team that she was about to release vital classified information to Captain Hikaru Sulu and so she was killed by her deputy Mosrene when he sliced through her environmental suit and thorax with a monoblade. (ST - The Lost Era novel: The Sundered)