Time Lord messenger (Genesis of the Daleks)

After a transmat beam used by the Fourth Doctor and his companions was redirected to Skaro, a Time Lord messenger visited the Doctor.

He explained to the Doctor that the Time Lords had forseen a time when the Daleks would dominate the universe and gave him a mission to disrupt the Daleks' timeline by preventing their creation, making them less aggressive, or identifying an inherent weakness. He also gave the Doctor a time ring to leave Skaro once the mission was complete. Then he vanished. (TV: Genesis of the Daleks, PROSE: Doctor Who and the Genesis of the Daleks)

Identity
Various conflicting accounts existed regarding the messenger's identity. (PROSE: The Dalek Problem, Lungbarrow, Divided Loyalties, AUDIO: Ascension)

By one account, this messenger was Deliavatsud, a director of the Celestial Intervention Agency who went rogue in an attempt to subvert the APC Net's predictions of total Dalek domination. He was subsequently tried for unauthorised intervention and executed by disintegration. (PROSE: The Dalek Problem)

By another account, the messenger was Ferain, the Director of Allegiance for the Celestial Intervention Agency and author of An Alternative History of Skaro: The Daleks without Davros. When Ferain arrested Leela, the Seventh Doctor recognised him from the trenches on Skaro. (PROSE: Lungbarrow)

According to one other account, this messenger was Valyes, who was sent in disguise by Narvin after the Daleks invaded Gallifrey. (AUDIO: Ascension)

By yet another account, the leader of the team who identified the Daleks' threat to the universe and developed a plan to stop them was named Jelpax. (PROSE: Divided Loyalties)

Further adventures
According to one account, following the failed intervention in Skaro's history, the Time Lord messenger's duties increasingly revolved around the Daleks. He watched as they planned a campaign called Pa Jass-Vortan in retaliation for the Time Lords' actions. When the Daleks used their time corridors to travel to Shoreditch in November 1963, (PROSE: The Slyther of Shoreditch) an event known as the Shoreditch Incident, (PROSE: Who Killed Kennedy, et al.) he travelled there to stop their mechanically augmented Slyther from tracking advanced technology in the region, which he assumed was the Doctor's TARDIS. First, the Time Lord researched the local culture and decided to order a half pint of bitter shandy from a local pub, where he encountered the Seventh Doctor.

The Time Lord explained the situation to the Doctor and agreed to return the Slyther to its home space and time if the Doctor would help him track it. Together, they travelled to the funeral parlour where the Doctor had stored the Hand of Omega and commandeered a black hearse. The Time Lord nervously stayed in the vehicle as the Doctor stole a piece of the undertaker's clothing from his house, then drove the hearse as the Slyther attacked. Struggling and screaming, he drove right through the fence of an electricity substation, leaving a deep bloody gash on his forehead. After the Doctor killed the Slyther, the Time Lord happily left using his Time Ring, disappearing with the creature's corpse after warning the Doctor about Pa Jass-Vortan one more time. (PROSE: The Slyther of Shoreditch)

Behind the scenes

 * In a deleted scene from the end of Return of the Cybermen, the Time Lord messenger would have appeared in the TARDIS to tell the Fourth Doctor that his failure to succeed in his mission had caused his own history to reoccur in slightly different ways and may lead to a Time War. This was meant to explain the contradictions between Return of the Cybermen and Revenge of the Cybermen, as well as between The Haunting of Villa Diodati and Mary's Story, and Human Nature and Human Nature.