"This is Doctor Weissenger, our chief medical officer and biologist."- Stevens
Dr. Elsa Weissinger was a doctor for PHARCOM, the Agency, and the IPCA. She was a minor antagonist in Syphon Filter 2, Syphon Filter 3 and Syphon Filter: Dark Mirror, while playing a supporting role in Syphon Filter: The Omega Strain. She later returns as a minor enemy in Syphon Filter: Dark Mirror.
Elsa Weissinger's birth occurred twenty-two years after Allied forces firebombed her hometown of Dresden during World War II, and the same amount of years before the collapse of the Berlin Wall reunified Germany. Weissinger would consider the timing an omen, and she believed it indicated that her purpose was to change the world.  Her high scores in school earned her a scholarship to the Institut fur Immunologie, Universitat which was founded in Hamburg, where she took a career in science. From there, Weissinger developed a relationship with Lukas Kaufmann and worked alongside him on research into biological weapons. Kaufmann explained his desire to rid the world of cancer and all diseases, and Weissinger soon sought the same "revolution."
Weissinger interned with Wyn Industries  and became one of the chief scientists when Jonathan Phagan founded PharCom. After Kaufmann faked his death and assumed the identity of Nikolai Jandran, Weissinger oversaw all responsibility for turning an ordinary virus into the genetically-programmable Syphon Filter. 
After conducting tests in Costa Rica, Wessinger agreed to work for the Agency as PharCom fell under federal investigation. Despite distrusting Agency personnel, Weissinger extracted the infected plasma of her former boss, Phagan, and prepared it for a shipment to Shi-Hao's rebellion. She helped trap the expelled Agent Gabriel Logan in a series of underground labs, but on his eventual escape he forced Weissinger to supply him with Lian Xing's vaccine prior to the facility's lockdown. 
The Agency still controlled her, and sent her to Australia for learning that Vincent Hadden and the arms consortium were behind their activities.  Weissinger had to test the virus on aborigines, and Mara Aramov left her behind when Commander Silvers of the consortium plotted to shut down operations. A joint Agency-MI6 operation involving Lian Xing and Maggie Powers recaptured her from the Australian desert, prompting Weissinger to give them a disc on Syphon Filter and the consortium. She then disappeared.
Weissinger met with Aramov again, as well as her employer Mihai Niculescu. Teresa Lipan also contacted her, and Weissinger joined the Agency. She assisted Lawrence Mujari in curing the Omega Strain, but murdered Dr. Jandran with a serum. Weissinger departed from the Agency rid of her past, and hinted that she would change the world.
Gary Stoneman tracked Dr. Weissinger to Mara Aramov in Narbonne, France, as the two had formed a relationship and conspired together away from Niculescu. Stoneman assassinated both before they could continue future plans.
Personality and characteristics
Elsa is a delusional narcissist who was born 22 years after Allied forces firebombed her home of Dresden during World War 2 and the same amount of years before the Berlin Wall's collapse reunified Germany. As a result, she considered the timing an omen and believed it indicated that her purpose was to change the world.
She developed a relationship with Lukas Kaufmann in her career with science and worked alongside him on research into biological weapons at the Immunologie Universitat found in Hamburg. Kaufmann explained his desire to rid the world of cancer and all diseases, and Weissinger soon sought the same "revolution."
Despite her initial plans to work with Kaufmann, she eventually developed a serum that would kill him, certain that she had to change the world.
Syphon Filter 2
- Colorado Mountains (Intro)
- McKenzie Airbase Interior
- McKenzie Airbase Exterior
- C-130 Wreck Site (cutscene)
- Agency Bio-Lab
- Agency Bio-Lab Escape (cutscene)
Syphon Filter 3
Syphon Filter: The Omega Strain
- Carthage, Michigan: Quarantine Zone (mentioned)
- Carthage, Michigan: Warehouse District (mentioned)
- Carthage, Michigan: Carthage Mall (cutscene and voice)
- Mazyr, Belarus: Krivorozhstal Mill (mentioned)
- Mazyr, Belarus: Belaya Vezha (mentioned)
- Sana'a, Yemen: Taherir Palace (cutscene)
- Minsk, Belarus: International University (mentioned)
- North Atlantic: Lorelei Salvage Rig (cutscene, no lines)
- Tokyo, Japan: Murukawa Tower (mentioned)
- Taguang, Myanmar: Irawaddy Basin (mentioned)
- Zurich, Switzerland: Niculescu Funds Tower (mentioned)
- Kiev, Ukraine: Chechen Terrorist Base (mentioned)
Syphon Filter: Dark Mirror
- Of all the characters who are killed, she is one of the few who has many possible death animations: she can be shot (by Stone or Mara); killed in a hit-and-run; set aflame (with the Flare Gun); killed in an explosion (with the SMAW, MGL or Calico HE) or hit with the taser.
- It is implied in Dark Mirror that she cheated on Mara Aramov by sleeping with Mihai Niculescu.
- In Syphon Filter 3's multiplayer, Weissinger is prone to taunting her enemies:
- Do I recombobulate your phenylalanine?
- Get back here, test subject!
- I got something for you!
- Death will look good on you!
- The coroner is waiting for you!
- I thought I already killed you!
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