A long time ago, there was a man who embraced the potential of time travel.
His name was Rassilon, of Gallifrey, and his influence made the people of that planet lords of time. They developed a purpose of studying history and space, their careful observation made them a confirmed aspect of time. He made preemptive efforts to ensure all aspects of time be controlled, his designed foresight made the Lord High President create a little focus group of potential rebels. Though children, these souls were deemed to be influentially chaotic to existence. They were called the Deca.
One would seek to be a Master of all.
Another would be pensive as a Monk, but anything but in his heart.
A third who would be obsessed with all War.
But two were quite infamous for their capability.
The Rani, a master of chemical mayhem.
And the Doctor, who would seek out all problems.
These last two, with the Master, were the dearest of friends.