Davros was Chief Scientist of the Kaleds towards the end of their thousand year war with the Thals on the planet Skaro. Confined to a mobile life-support system, Davros developed a final solution to end the war: The Daleks – mutated Kaleds robbed or morality and with added aggression, placed inside armoured shells called the Mark III Travel Machines. However, his own people rejected the notion, and in retaliation he gave the Thals the formula to destroy the Kaled dome. Safe in the bunker below, Davros released the Daleks on an unsuspecting world. However, the Daleks turned upon their creator, and left him for dead in the bowels of the city on Skaro.
Years later, the Daleks sought his help to defeat their logical stalemate with the Movellans and then again to defeat the Movellan virus. Later he became The Great Healer, turning the bodies of the dead into food, or new “Imperial” Daleks. His grip on the Daleks weakened, as a renegade faction grew up – loyal to the Supreme Dalek - plunging them into civil war.
He commanded Dalek forces during The Last Great Time War, and was seen flying into the jaws of the Nightmare Child. Rescued by Dalek Caan, Davros constructed the Reality Bomb, but was foiled by the Children of Time.
Escaping the burning wreckage of the Crucible, Davros traveled to Skaro where he used his servant Colony Sarff to lure the Twelfth Doctor to his lair. Predictably, as ever, his scheming was undone though the scientist was last seen in the company of Missy. What treachery could they be planning...?
Yes. I would do it. That power would set me up above the gods. And through the Daleks I shall have that power!
You hesitate Doctor. If I were you, I would be dead.
I will teach you the folly of your words, Doctor! I will destroy you, and demonstrate the power of the Daleks!
Never forget, Doctor, you did this! I name you, forever. You are the Destroyer of Worlds!
It took me so very long to realise it was you, standing at the gates of my beginning. And here you are at the end.