Dr. Anton Koenig is an antagonist that appears in Prototype 2. He was the lead virologist of Gentek and responsible for its major projects conducted in New York City. After the second outbreak occurred, Koenig worked with Blackwatch and experimented on various infected creatures. He was eventually recruited by Alex Mercer and became one of his Evolved.
After James Heller became infected with the second strain of the Blacklight virus, he was recovered and experimented on by Dr. Koenig. He was fascinated by the fact that Heller was still alive despite being flooded with the virus. Wanting to put Heller through a series of tests, his fascination grew after seeing the initial data recorded, as he had never seen anyone like Heller before.
When Colonel Douglas Rooks gave the order to destroy Heller, Koenig objected vehemently, instead advising Heller to consume more infected to survive, a choice which put him at odds with the Colonel. After Heller escaped from the lab, he targeted the doctor, not knowing that he was working with Mercer.
Eventually, Heller cornered Koenig at one of the bases. Koenig tried to convince Heller that he was trying to help him by revealing the locations of Project Orion, a Blackwatch project creating super soldiers. Heller believed him and set out to destroy the project. However, after Heller consumed one of the leading scientists he learned that Koenig was observing him in order to measure his strength, and that he now knew how to kill him. Enraged at this act of betrayal, Heller contacted the doctor and told him that he was coming after him.
Koeing contacted Blackwatch to evacuate him, but Heller managed to destroy the soldiers guarding the base where he was hiding. During the evacuation, Koenig boarded one of the gunships and ordered the pilot to attack Heller instead of evacuating. However, Heller destroyed the gunship and tried to consume Koenig, only to be attacked and discover he was one Mercer's Evolved.
Koenig stated that Alex Mercer required someone inside Gentek to get information. He then began to mock Heller, claiming that he wanted to prove to Mercer that he should be his second in command, and to do that, he had to kill Heller. The two then fought to the death. Eventually, however, Heller overpowered Koenig and consumed him, gaining the knowledge that Mercer had spies in both Gentek and Blackwatch.