I.M. Foreman was a Gallifreyan monk who lived on Gallifrey but was driven from the monasteries following Rassilon's Intuitive Revelation. They were not a Time Lord, but were able to regenerate due to their order having received its own version of the Rassilon Imprimatur. (PROSE: Interference - Book Two)
Having been exiled to the wilderness after the dissolution of the old religious orders, the lone Gallifreyan priest found twelve individuals, none of whom had any memory of who they were, but whom he soon realised were his twelve future incarnations. The priest eventually named himself I.M. Foreman, and removed his own eyes to sharpen up his telepathic abilities. After acquiring time-travel techniques from other wasteland refugees, the thirteen formed I.M. Foreman's One-Species Nongenetically Engineered Travelling Show, a complex space-time event that could travel through time. As a priest, he had been given the gift of regeneration, but in those days it was highly unstable, meaning that each incarnation tended to incorporate the DNA of whatever the previous ones had eaten: each of Foreman's bodies was more alien and mutated than the last.
He eventually arrived on Dust, where his true nature was revealed to the Third Doctor and Sarah Jane Smith. When the Remote attacked the planet, Foreman's first twelve incarnations were forced to release Number 13, the most unstable of all his regenerations, which tried to eat everything and absorb it into its own structure.
In order to conclude the time loop and prevent the death of the past twelve Foremans causing a paradox, the Doctor directed the other incarnations into the show, linked it to the TARDIS, and sent them back to Gallifrey's distant past. Arriving at its destination with no arrival site prepared for it, their Travelling Show exploded as it ended up back in the Dark Times just before the first I.M. Foreman found the show. The resulting explosion and the fall from the ship triggered a regeneration for all twelve aspects, each of them changing into their next self while losing their memories due to the trauma of the damage and the limitations of their current ability to regenerate.
Back in the present, after Number 13 consumed the attacking Faction Paradox fleet, the Doctor was able to convince it to blend with the planet Dust to turn it into a new, vital world. With the crisis concluded as the planet grew more vibrant, Foreman's consciousness formed a bond with Magdelana Bishop and inhabited her body with her consent. In this form, Foreman spent two days in the company of the Eighth Doctor, during which she talked with him and spent the night with him. (PROSE: Interference - Book Two)
76 Totter's Lane
Foreman's show spent some time in 1964 at 76 Totter's Lane, where its arrival retroactively created a junkyard so that it would have a form to occupy. (PROSE: Interference - Book One) This was the same junkyard where the First Doctor encountered Barbara Wright and Ian Chesterton; Susan Foreman adopted her surname from the lettering on the gates. (TV: An Unearthly Child) When the Third Doctor learned of Foreman's existence, he realised that the TARDIS had been drawn to the scrapyard in 1963 because it had sensed the show's future presence there. (PROSE: Interference - Book One)
On Dust, Foreman dressed like a local townsperson, though he stood out because he looked too clean and proper. He wore a blindfold, a strip of red cloth wrapped across his eyes and around his ears, with dark smudges that may have been dirt or blood; this made it difficult to tell his age. He wore a waistcoat and trousers and carried a gold-edged pocket watch. As part of his show, he manifested stigmata, bleeding copious amounts of thin blood from circular holes in his palms; when not performing, he wore a pair of shoddy white gloves.