The information here comes from a post made by the official account on Hoyolab on 29 April 2022. (Many of these exist in the database already and have been edited slightly.)

People know very little about the mysterious beings that dwell in the deep stellar ocean. Constrained by their limited cognition, intelligent lifeforms can only slightly perceive the Paths that Aeons tread upon, and rely on mere concepts and theories to vaguely comprehend the vastness of their powers. Eventually, through spoken legends, these Aeons became the embodiments of abstract concepts.

If anyone finds themselves treading on the Path of an Aeon, they will be inundated by a distant sensation, like being struck by a glance from light-years across the galaxy. Many believe that this is the only connection the Aeons and mortals can ever have.

“Countless shooting stars streak across the night sky… If you can pick the right one, it will carry your wish to thousands of distant worlds.”

— Adrian Spencer Smith, Fables About the Stars

There are three directions on the wheel of destiny — the unknown, the known, and the unknowable. The idea of the unknown is tolerable, however, the unknowable sounds more like a challenge. Akivili left the isolated world of Pegana and continued to explore the unknown edges of the universe, hoping to find the edge of existence. Unfortunately, Akivili's destiny was abruptly ended due to an accident.

“If the increase of entropy is a fundamental law of the universe, then the heat death would be the inescapable destiny of the material world. So, why is it that we bother to struggle to survive? Expansion, fusion, and then annihilation. If we wish to welcome the new, then we must first come to an end.”

— From a scientist just before pressing the button for nuclear detonation

The birth of the universe is a mistake. If civilization is a cancer emerging quietly from the boundless stars, then war is the only common language known to all intelligent life.
To correct this mistake and to clean up this tainted universe, Nanook became the avatar of entropy.

“With no end to hate and no boundaries to war, how much more worry can you shoulder?
With determined eyes and bow drawn, the Archer Lord bears no second thoughts in mind.”

—Xianzhou, Worlds History as a Mirror

The roaming Aeon, also known as the Archer Lord of Fate wanders endlessly between worlds to vanquish the undead beings that once plagued their homeworld.
The cost of the hunt was never a consideration for Lan. In the eye of Lan, there is no difference between salvation and total destruction.