Second Drax

The Second Drax was a renegade Time Lord with a knack for tinkering and engineering.

Biography
Drax had already escaped from Gallifrey when the Doctor was expelled from the Time Lord Academy. (PROSE: Divided Loyalties) Unlike other renegades like his contemporaries, the Master and the Rani, Drax purchased his TARDIS instead of stealing one. (PROSE: Doctor Who and the Armageddon Factor)

Upon becoming a renegade, Drax travelled the universe, doing repair and maintenance work in the fields of cybernetics, guidance systems and armaments. He also committed cons. When his TARDIS suffered a breakdown in its hyperbolics, Drax was stranded on Earth. He engaged in criminal activity to procure replacement parts and did time in Brixton prison for over ten years where he acquired a Cockney accent to help him survive inside, which would later become a trademark through several of his regenerations, though the Twelfth Drax would tell Romana II he had lost it a few regenerations ago, from that incarnation's perspective, during a con.

Later, the Black Guardian's agent, the Shadow, imprisoned Drax and forced him to build and maintain a giant computer called Mentalis on the deserted planet Zeos. Mentalis carried out a war against the neighbouring planet of Atrios.

450 years later in their personal timelines, (TV: The Armageddon Factor) Drax, then in his second incarnation, (AUDIO: The Trouble with Drax) and the Doctor met again. While searching for the last segment of the Key to Time, the Fourth Doctor and Romana I arrived on Zeos. Drax, under the Shadow's orders, reluctantly led the Doctor into a trap. Drax claimed he hadn't expected the one looking for the Key to be the Doctor. Briefly, the two reminisced though at first, the Doctor needed a moment to remember him. Easily seeing through Drax's pretence, the Doctor talked him into joining forces against the Shadow. With Drax's assistance, the Doctor recovered the final segment of the Key to Time. Afterwards, Drax stayed on Atrios to help rebuild that world. (TV: The Armageddon Factor) During that time, Drax had hacked the directional unit of the Doctor's TARDIS. (AUDIO: The Trouble with Drax)

Alternate timeline
In an alternate timeline Drax cooperated alongside the Master, the Monk, and the Rani to try to destroy the world using a DNA recombinator, turning the human race into a gestalt consciousness which could be used as a weapon to conquer the universe. (PROSE: The Quantum Archangel)

Behind the scenes

 * Although Drax's TARDIS is somewhere around in The Armageddon Factor, only components from it are seen on-screen. The interactive Make Your Own Adventure with Doctor Who book NOTVALID: Search for the Doctor included Drax as a character, and described his TARDIS as taking the shape of a convertible car, the registration plate of which read: "TARDIS".