Omega (The Evil of the Daleks)

"That is my name. The Doctor gave it to me. Yes. He is my friend!"

- Omega

Omega was a genetically altered Dalek, created by the Doctor. He isolated the Human Factor from Jamie McCrimmon and implanted it in three Daleks.

If he had not done this the Daleks would have destroyed the TARDIS. (DW: The Evil of the Daleks)