Who is Anthor Pelleas from Second Foundation and what is their importance?

Anthor Pelleas introduces himself to Dr. Darell as a student of Dr. Kleise, and together, they form a group of conspirators to help find and destroy the Second Foundation. When the Foundation suceeds in defeating Kalgan in a war, Pelleas almost succeeds in convincing the conspirators that Kalgan is home to the Second Foundation. What he doesn't know is that Dr. Darell has suspected him to be a member of the Second Foundation all along and proves it by disabling his mind with his Mental Static device. Under the device's influence, Pelleas admits the Second Foundation is located on Terminus. However, this also proves false, pointing to the idea the Second Foundation conditioned his mind to withhold information, even under extreme pressure.