Lodian

Lodian was a humanoid Dalek scientist working in a secret base in the Polar Mountains along with Yvric and Zet. He and Yvric discovered the location of the planet Earth, and constructed a spacecraft to go there. When the neutronic war occurred, the pole shifted and all three were frozen alive in ice.

Centuries later, a Dalek hoverbout accidentally revived them, and they soon determined that they were the last of the original Daleks and that Yarvelling's creations had become the rulers of Skaro. Lodian was the only one of the three to recognize that the Daleks were evil, and when Yvric was exterminated, he told Zet about Earth and the spacecraft. However, Zet knocked him out and handed him over to the Daleks.

Lodian escaped and made it back to the spacecraft, which he destroyed, sacrificing himself and killing Zet so that the Daleks would not learn of the existence of Earth. (TV21: Legacy of Yesteryear)