Geras is one of the oldest stars in our known universe, forming in 13.676 billion BCE (just 124 million years after the Big Bang). It exists in the galaxy Ambrosia, within the outer reaches of the Dryas Cloud. It wandered a dark and empty universe, populated with nothing but hydrogen and photons, until it was captured by Ambrosia during its formation between 13 and 11 billion BCE.
In 4 billion BCE, it had a close encounter with a quadruple star system, stealing many planets and wreaking havoc upon the system. It now has 3 planets, one of them inhabited by an aquatic species (known as the Merbrekians) in the process of adapting to land. The planet in question is known as Merbrek, and the majority of its surface is covered in a purple carnivorous flora that posed a massive problem to explorers first stepping foot on Merbrek.
Geras, and its planets, appear to be under the influence of a temporal anomaly that's causing things to progress extremely slowly. Days on its planets are normal and the species on the planet act ordinarily, however the planets take hundreds of millennia to do one orbit around Geras, and there are no fossil records of Merbrek's species ever evolving.
In 41,583 CE, a signal was detected by researchers. The signal detected was extremely far off, at the edge of Geras' gravitational influence. When ships attempted to reach it, the signal faded away and was redetected at the opposite side of the system. After chasing the signal for weeks, telescopes were pointed at the signal, revealing a dark purple object of unknown size, flashing with light like many thousands of bombs were going off. It's possible that this object is what's causing the temporal anomalies.
13.6 Billion BCE: Geras forms.
4.2 Billion BCE: The star Geras has a close encounter with another Ambrosian star, taking 3 planets.
10^101.5 CE: The last black hole explodes. Geras and its 3 planets become the last celestial bodies in existence.
10^150 CE: The Merbrekians finally evolve to a type I civilisation.
10^19^16: Geras explodes, taking its planets and the Merbrekians with it.