Davros's trial (Revelation of the Daleks)

Following the Dalek-Movellan War, Davros was captured by the Daleks and placed on trial on their home planet, Skaro.

Capture
Having been alerted by Takis, a worker at Tranquil Repose on the planet Necros, Daleks loyal to the Supreme Dalek came to Tranquil Repose where they captured Davros. Informing him that he was to stand trial "for crimes against the Daleks", the Daleks took Davros with them. (TV: Revelation of the Daleks)

En route to Skaro, the ship carrying Davros crashed on the planet Lethe. Davros was rescued. He set himself up as "Professor Vaso", altering the perceptions of the humans on the colony so they would not recognise him as the "Great Healer". He attempted to create a new machine, a Juggernaut based on a Mechanoid design.

Lethe's atmosphere prevented the Supreme Dalek retrieving Davros directly, but its forces intercepted the Sixth Doctor's TARDIS, forcing him to serve as an agent of the Daleks and stop Davros' researches and manipulations. The Doctor discovered two of Davros' Necros Daleks had survived the crash, but were destroyed following Davros' final gambit on the colony and the Supreme Dalek's intervention. (AUDIO: The Juggernauts)

The trial
According to one account, Davros was then taken to Skaro, where he was put on trial by the Dalek Emperor. Before a sentence could be passed, however, the Sixth Doctor released a virus onto the Daleks, saved Davros, taking him on board his TARDIS. (COMIC: Emperor of the Daleks!)

By suggestion of the Doctor, (COMIC: Up Above the Gods) Davros hid himself on Spiridon, along with his empire of Daleks. The Daleks who had put him on trial before came to return him to Skaro, but his Daleks held them off. Davros detonated the planet, killing the Daleks. He woke highly injured, four days into the Dalek civil war, in a new casing as the Dalek Emperor. (COMIC: Emperor of the Daleks!)


 * For more background on and an account of the war that followed between Dalek factions, see Imperial-Renegade Dalek Civil War.

According to another account, Davros encountered the Thal Lareen while en route to Skaro. Lareen was using a stealth suit that made her invisible to Dalek scanners. Lareen attempted to find Davros' "good side," and believed she had succeeded. She gave Davros a capsule containing an enhanced version of the Movellan virus and asked him to release it during his trial. This would destroy all Daleks on Skaro, and make Davros a hero.

Upon arriving on Skaro, Davros found that the Supreme Dalek had a new casing created. The Supreme Dalek planned to be moved to the new casing and named Emperor of the Daleks after Davros' execution. During his trial, Davros told the Daleks of the Movellan virus, and proved his loyalty to the Dalek cause by refusing to release it. He then told them that Lareen was on Skaro and ordered them to exterminate her. The Daleks were impressed with this show of loyalty, and named Davros Emperor of the Daleks. (AUDIO: The Davros Mission)