The sun rose, and Mokou woke up. The sun set, and Mokou went to sleep.
All living creatures must die.
She knew Kaguya and Eirin were keeping a close eye on her. Plying her with medicine to retain her sanity. Dosing her with it even as she slept. She forgave them for it even as she cursed them to the depths of any Hell that remained. After a while, she forwent the cursing.
All living creatures must die.
She made an effort, sometimes. For thousands of years at a time. Even without anyone to live in it, the world kept changing. She bore silent witness to the slow waltz of tectonic plates, and gazed placidly upon the hurricanes, volcanic eruptions, and electric storms, erratic beats in the steady pulse of the Earth.
All living creatures must die.
Mostly, however, she slept, in deep dreamless slumber provided by Eirin's drugs.
alllivingcreaturesmustdiealllivingcreaturesmustdiealllivingcreaturesmustDIE
And just like that, like any other day, a fiery sun rose on her second millionth birthday.
Mokou laughed.
Two million.
Two drops in the ocean.