The Eminence was a gaseous entity and psychic force that encountered the Doctor on several occasions.
The Eminence travelled across the universe in teleportation caskets. It could control the minds of any being it came into contact with, as long as it inhaled the breath of forever, turning them into its Infinite warriors. (AUDIO: The Seeds of War)
The Eminence was first created by Markus Schriver in his attempt to allow astronauts to control their ships by using only their minds. According to the Master, the Eminence were created from re-engineering mnetic particles at the molecular level, which created a neural compound that mimicked the human brain. The Master added some extra ingredients, such as a scoop of residual vortex emissions for energy storage and durability which gave them an orange glow, silicon activators which allowed them to manipulate logic gates as well as coming in handy as calcification agents which allowed the creation of the Infinite warriors. (AUDIO: Masterplan)
Schriver later cooperated with the Daleks on the development of his gas. He transferred his consciousness into his creation, thus becoming the original Eminence. He called the gas the Mnetic Neural Network, the MNN gas, and the Eminence name was a corruption of MNN. However, his consciousness was joined by the Dalek Time Controller's and its desire to conquer and enslave, as well as the consciousness of Molly O'Sullivan, who moved it to the very end of the universe. (AUDIO: Eye of Darkness)
It was at the edge of the universe where the Eminence first encountered the Doctor. The Orpheus travelled to the Eminence's location and attempted to siphon its power in order to get home. The Eminence began to possess the crew of the ship. (AUDIO: Time's Horizon)
The Doctor first fought the Eminence in his fourth incarnation on Delafoss. The Eminence created a ship called the Infinite, which it planned to use to end its war against the Earth Alliance. It breathed its breath of forever into the Doctor, and left him in command of the Infinite. The Doctor used his telepathy to trick the Eminence, and destroyed the Infinite. The Eminence subsequently lost its hold over Delafoss. (AUDIO: Destroy the Infinite)
The Eminence spent many years at war with humanity. The planet Kalsos was on the front lines of the war.
A thousand Eminence teleportation caskets travelled to the Nixyce system with the intention of taking over humanity. Seeing that in a possible future the Eminence would end up as the only life for in the universe, the Time Lords sent the Master to steal one of the caskets. The Master and took it back in time to 1970s London and experimented on the Eminence. When the Eighth Doctor came to investigate, he opened up the link to the Eminence in his mind and allowed the Eminence to pilot the Master's TARDIS. The Master managed to expel the Eminence into the Time Vortex. (AUDIO: Eyes of the Master)
The Daleks detected the presence of an Eminence fleet at the edge of the Nixyce system. (AUDIO: The Traitor) The Eighth Doctor teamed up with the Daleks against the Eminence. The Dalek time controller used the weapon they had built on Nixyce VII to destroy the Eminence fleet. (AUDIO: Time's Horizon, Eyes of the Master)
Heron's World was on the fringes of their war. There they got there Infinite warriors to inhabit the remainders of the population there. the Master attracted their attention. They tried to use the Breath of forever on the population but Molly O'Sullivan's regenerator particles stopped them. (AUDIO: The Death of Hope)
The Master, the Doctor, Liv Chenka and Sally Armstrong went back to their creation to change it. The Doctor and Liv planned to avert it, whereas the Master and Sally wanted to get the Eminence under the Master's control. The Master released the Eminence from his mind so that they could control the ship they would crash on. But the Eminence didn't do the Master's bidding and started to try and kill the Master and the Doctor. (AUDIO: Masterplan)
The Eminence enter into an alliance with the Master where they both could control the human race through Dark Eyes. However, the Doctor told the Eminence that the Master planned to betray him and told the Eminence how to take down the Master. The Doctor tried to destroy the Eminence by dispersing the Retro-genitor particle through Walter Vincent. (AUDIO: Rule of the Eminence)