The Master later resurfaces as he’s put on trial for the Daleks for his “evil crimes” (this is not elaborated on, really, as the Daleks aren’t exactly innocent either.) he’s then “exterminated” and his ashes are retrieved by the second Doctor, but this isn’t any ordinary urn-The Master has somehow preserved his essence in some slimy goo.-slimy goo which then escapes and sabotages the TARDIS console, causing the Doctor to go through a series of events that lead to another regeneration.
The Master’s slime form then escapes and posesses an EMT, Bruce.
However, the Master’s possession make’s Bruce’s eyes somewhat strange, and he has to cover up using sunglasses. He then enlists the help of a local youth-Chang Lee-and deceiving him, puts in motion a plan to steal the Doctor’s regenerations (once again using the eye of harmony), as the Bruce body is technically ‘dead’ and prone to decay.
When he finally captures the newly-regenerated Doctor, he dons a Time Lordish garb.
However, the Doctor is able to defeat the Master once again, and he falls into the Eye of Harmony where he apparentally dies….but this is the Master we’re talking about…
The Time War erupts-a huge conflict across space and time featuring the Time Lords battling the Daleks. The Doctor is forced to take drastic measures-regenerating into a new, harder incarnation-
….and the Master is also resurrected (and presumably given fresh regenerations), as the Time Lords feel his ruthless nature will make him the perfect warrior against the Daleks. However, when he witnesses the Daleks conquer something called the “Cruciform”, he panics, using the Chameleon arch to disguise his body as mind as human. It’s so perfect a disguise he has no knowledge of his former evil nature-but something does remain-His intelligence, and also the sound of drumming in his head. His essence remains in a fog watch.
“Yana” (Short for You Are Not Alone) eventually becomes an elderly, kindly scientist trying to help the last humans at the end of the universe escape to a rumored paradise-the so-called “Utopia”. However, the arrival of the Doctor and his companions tips him off to the watch, and soon “Yana”‘s true nature asserts itself as his memories come floating back from the watch.
Killing his scientist friend, and attempting to trap the Doctor and his friends, he also takes control of the TARDIS. However, he’s fatally shot by his assistant, causing him to regenerate into a more youthful state, not unlike the Doctor’s current incarnation.
Next: Harold Saxon, The End of Time, and “Who is Missy?”