Doctor Roger Kadar is a scientist working in Charleston, South Carolina.
Dr. Kadar formerly worked at the University of South Carolina, teaching nuclear physics. Sometime after the invasion, Arthur Manchester found Dr. Kadar and struck a deal with him to run Charleston's power grid.(Collateral Damage)
In At All Costs, Anne Glass comes to Kadar and asks him to devise a way to test the DNA of de-harnessed kids (and unknown to Kadar, Anne's baby Alexis) for any abnormalities. The doctor is able to run tests and finds that all the de-harnessed kids are healthy, but Alexis is not. Kadar discovered that Alexis's DNA is combined with alien DNA. When he talks to Anne about reporting Alexis's problem, Anne knocks him out.
In Search and Recover, Kadar explains to Vice President Marina, the Masons, and Captain Weaver what happened with Anne. He reveals to them the hybrid nature of Alexis. Later, Marina finds him running test for Lourdes to check the humaness of the other babies born in Charleston. She gives him photographs of the Volm "cannon", asking him to determine what it will be used for. After studying the pictures, he concludes that it is "overkill", saying that it stores more energy than is necessary for the plasma armature of the machine. He implies that there is something not quite right about the machine.
- Dr. Kadar suffers from agoraphobia, which is a fear of going outside. He also has Asperger's Syndrome which explains why he's anti-social and why he doesn't like to leave his laboratory.