Kasrene was a Tholian who served as an ambassador in the 23rd century. During that era, he served as an envoy to 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 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)