Katia Loenstern (1970-2006) was an Israeli American Krav Maga class instructor who taught self-defense lessons. She had taught Krav Maga classes, with Sam Fisher being one of her students that attended. Due to his dangerous line of work, and fear of placing her at risk, Fisher tried to avoid becoming too close to Katia, merely flirting at most.
After a while, however, the two became romantically involved and Katia was Fisher's girlfriend for a short time. After a coincidental meeting in Los Angeles, California, she is shot and killed by Yvan Putnik who was actually trying to kill Sam Fisher.
2005: Splinter Cell (novel)
Katia Loenstern taught Krav Maga classes during this time to a group of students, one of them being Sam Fisher. Although Fisher really liked Katia, he distanced himself because of his work as a Splinter Cell and didn't want to put her in any danger by getting romantically involved with her. Despite not wanting to get close to her, he eventually accepted her request to have coffee together after the Krav Maga lessons.
2006: Operation Barracuda
For Fisher's 49th birthday, Katia visits him at his house and prepares him breakfast for his birthday. This was their first intimate and sexual encounter, Fisher notes that it had been a long time since he had been in a relationship since Regan's death. During one encounter in Los Angeles, however, Katia was shot and killed by Yvan Putnik who was attempting to instead assassinate Sam Fisher.
- Katia appears in the Splinter Cell novel and Operation Barracuda, however, she is never mentioned or referenced during any of the official games in the Splinter Cell series.
- Katia is one of three women that Sam Fisher had become romantically involved with during his career in Third Echelon. After the death of Katia, in Splinter Cell: Double Agent (Version 2), Fisher developed a relationship with JBA member Enrica Villablanca and later with his former student Kimberly Gillespie (Tom Clancy's Splinter Cell Endgame).