Anyone - Nanite Control - Suprised

Anyone- no holds barred.

Nanite Control- About fifteen years ago a brilliant scientist unleashed his Nanites on the world. This was of course a great concern to the world’s many governments. The nanites spread themselves across the globe infecting virtually every person on the planet at such a rapid and alarming pace that there was no stopping them. Tracked to the source, the scientist was killed before they could him to deactivate them, and in the process locked them out of his command system forever.

However… soon enough the concern turned to glee as the newly infected hosts began to benefit from the Nanite intervention. Bodies became healthier, on a basic level altered. Gone were the epidemics of obesity. Even the signs of aging were removed, although it was found that people could still die. Society’s citizens found themselves living longer healthier lives. A more sinister problem emerged. The Nanites automatically adjusted the fertility rate of the population down in order to compensate for the longer lives of their hosts, but too much. With nobody to make adjustments to the algorithm the number of births is soon eclipsed by the number of deaths- a serious problem, but one our hero will surely be able to solve.

Our protagonist gains access to the Nanite command system. They can make changes to either themself or, in time, anybody touched by the Nanite technology. The changes can be either physical or mental, but trend towards the physical, and mental changes need to have some underlying biological mechanism that can be adjusted.

Surprise- Most will be surprised if they become aware of changes.

** Author note I borrowed most of this prompt from a story branch that I now can’t find, but let me know in the comments if this is something I should pursue.