Renewal technology would prove fiendishly difficult to reverse engineer. For decades, only the original development team could truly make the stems cells dance to their tune. In that time, the five lead researchers leveraged their knowledge to amass vast wealth and power, for they alone held the keys to eternal youth. Availability was scarce in those early years. Presidents and kings, celebrities and the fabulously wealthy, all would grovel for a second chance at life.
The Five Tenno, as they came to be known, were each driven men in their own right, and their passions and deep obsessions grew more acute with each subsequent life. Individuals would often find themselves the object of their capricious fixations. The Twins, being each the other's obsession, proved the most benign. The Little Empress, with his continued pursuit of human experimentation, remains feared to this day.
It is unclear how much their later mental deterioration into delusions of grandeur, if indeed they can be called delusions, was from their incredible accrued influence, and how much arose from flaws in the original process of genetic recombination for which they themselves were the first test subjects.