Chris Cwej's Superiors

The Superiors were one title by which the powerful masters of Chris Cwej were known, alongside other names such as the Shadow People, the House-Dwellers, the Lords of Jewel, and, more informally, Those Lot Up There. Influencing from the Base of Operations, they held domain over the Linear Universe. (PROSE: A Bright White Crack)

The term "mysterious superiors" was sometimes used to refer to the people of Iris Wildthyme (PROSE: From Wildthyme with Love, The Wildthyme Effect) and the Doctor. (PROSE: Verdigris)

On Earth, the term of "superior" could also generically be used to refer to individuals higher up in one's hierarchy than oneself, but not necessarily of a different species than oneself. The Brigadier had to deal with the whims of his own "superiors", (PROSE: Who Killed Kennedy) as did a guard who once captured Panda. (PROSE: Future Legend)

Nature
Chris Cwej thought of his Superiors as "the most complex pan-dimensional beings the Totality had ever produced". (PROSE: A Bright White Crack)

Culture
Having been responsible for the creation of the Linear Universe, they were notoriously unwilling to let any other species of cultures within their dominion recreate the scientific principles that gave them their power, as it would allow those lesser beings to challenge their rule. (PROSE: A Bright White Crack)

Early history
Chris Cwej knew his Superiors played an immense part in the universe: they created the Linear Universe,and "wove Their likenesses into the biology of every being". (PROSE: A Bright White Crack)

Using Chris Cwej as their agent
The Superiors used Chris Cwej as their agent, having "stripped his flesh away" and turned him into an electronic consciousness whom they could reincarnate on cue. (PROSE: A Bright White Crack)

They once sent Cwej to the Psychosphere. (PROSE: Collective Unconscious)

Undated events
The Third Doctor was sometimes sent on missions across time and space by his "mysterious superiors", the Time Lords. (PROSE: Verdigris)

Iris Wildthyme had "mysterious superiors" who once tried to make Panda their Supreme Being. (PROSE: From Wildthyme with Love) Iris once lied to Alice Liddell that they had to stop travelling together because Iris' mysterious superiors would disapprove of the changes to history. (PROSE: The Wildthyme Effect)

When Panda travelled with a future incarnation of Iris, he began to suspect that she had blown up her mysterious superiors at the end of the Tim War. (PROSE: From Wildthyme with Love)

Behind the scenes
Most everything about the treatment of the Superiors (as a distinct temporal faction rather than a generic term for high-ranking officials) in Cwej: The Series suggests they are intended to be the higher-ups of the Time Lord hierarchy, or simply the Time Lords themselves — mirroring the use of the phrase "mysterious superiors" to refer to Iris Wildthyme's kind in some of Paul Magrs's works.

However, the stories which feature the Superiors typically do not have the license to feature Gallifrey and its denizens directly, and especially in light of the Magrsian usage, they could just as easily be interpreted as the Clockworks, or indeed as the High Evolutionaries in general rather than specifically the Great Houses.