Isaac Newtman

Isaac Newtman was the creator of the regeneration potions, he wanted to stay living on but as his death was approaching him faster he decided to face his fate.

Isaac Newtman would use up all 12 incarnations of his first cycle, He worked hard on this science project on gallifrey to design a

specialised regeneration locked inside a potion bottle so that whoever drank the potion would change their DNA and grant them a new fully regeneration cycle.

Isaac used the first attempt as a test which triggered a bad regeneration which later down the line would affect him until his death..

He was the greatest timelord ever except for Rassion.

Appearance
Isaac's 26th and Final Incarnation worn purple and white robes and light blue Armor underneath with brown pants. He had dark brown hair, a chin beard and his age is around 1000 years old. His magic box was given to the people of Nirvana to keep as a gift

His 23rd Incarnation was Ginger and angry

He had earlier incarnations which stayed on Gallifrey

The Magic Box
Nobody's episode 7 explains how Isaac and Max arrived on nirvana and Isaac becoming a magician / wizard.

few years later having been a dead and empty magic box left for nirvana, it detects danger of an explosive event it sends itself far away and never to be seen again as the whole of nirvana ignites with a huge explosion and burns the planet.

Now your probably wondering how did Joe get a Tardis well during the time he was away on holiday he came back experimenting in his underground lab and found a magic box appeared out of nowhere it was then redesigned as the clown box.

Leaving notes behind
Isaac Newtman was very clever, there was a much bigger plan than his and he called it. Notes of his work was sent through a wormhole that Isaac opened up and sent it to the nobody's world.

Other events that happened in the timeline
Isaac Newtman invented cellular system travel in the year 3009 during his 6th incarnation who shared a resemblance to human from London with White hair

Death
In nobody's season 2 episode 2 max suffers from her loss, Isaac is dragged into a cave and killed by his own work. He knew about his fixed death and wanted to protect Max as much as possible.