Aesir, The God of Chaos

Aesir, The god of Chaos also known as the Overseer is a character from the Bayonetta series who debuted in Bayonetta 2. Aesir is the one who was choosen to rule over the World of Chaos after the struggle which created the Trinity of Realities. He choose to give up his powers to entrust humanity with his very own eyes, the Eyes of the World, as a result, Aesir was split in his good and evil halves and humans gained free will, something no other creature from the Trinity possessed.

The creation of the Trinity of Realities
After the creation of the Trinity of Realities, Aesir was chosen as the ruler of the World of Chaos, also known as the Human World. Watching over humanity, time, and space, he came to pity humanity for their naivety and lack of free will. He would then grant them free will and bestowed the his Overseer powers to them, in which became known as the Eyes of the World this separated his soul in two entity: Loptr and Loki. Because of this however, humanity gave birth to the negative qualities and sins of the world which would later give power to Loptr, his evil half. This evil half would later regret giving the Eyes to humanity and sought to retrieve them.

The return of Aesir
Aesir is recreated in Bayonetta 2 when Loptr, reclaims the Soverign Power from Loki, and the Eyes of the World from Balder and Bayonetta (character)[Bayonetta. He then sough to rule over humanity like he did in the past and challenged Balder and Bayonetta as the God of Chaos only to be stopped by Loki who reveal that the true power of the God of Chaos is "nothingness", the power to erase anything and everything from the world with it, he destroys the Eyes and revert Loptr to his normal form making him vulnerable to his opponents' attacks and ending the second reign of Aesir.

The Legend of Aesir
This is the complete version of the Legend of Aesir as told in Bayonetta 2:

"The Legend of Aesir... A legend from the dawn of time.

Nobody knows where the world came from. A struggle caused the Trinity of Realities to be split into three realms: light, darkness, and chaos. Obviously, our world was the one born from chaos. The three worlds all needed rulers. Most of all, ours. And the one that ruled the chaos became known as Aesir. Aesir spent the first eternity quietly looking upon the Earth from his holy mountain. Where we only see reality and make it match our rules of the world, Aesir saw through reality, and those visions became our world. These observations became Aesir's power. Aesir's eyes were truly the eyes that created the world.

However, Aesir pitied the humans for their naivety and lack of free will, so the power he wielded was split into two equal halves and entrusted each to humanity's instincts: the Right Eye of Light, and the Left Eye of Darkness. By dividing the power of the eyes of Aesir, humans gained free will... They could now choose. With control of the Eyes of the World, the eyes that determine destiny, humans could choose their own paths. They awoke to their own identities. Man is but a reed, the most feeble thing in nature, but now we were thinking reeds, and we took our big first step towards grand prosperity.

The inheritors of the eyes of Aesir had been granted the power of creation."

Hierarch of Laguna
"Light, darkness, and chaos. When the three world were divided at the dawn of time, Aesir was chosen to rule the World of Chaos. Possessing the power of the "Overseer", he existed in a dimension different from our own, watching over infinite possibilities that layered to form history from a viewpoint surpassing that of time and space. His name, Aesir, is to signify a God in meaning, yet it has no connection to faith, morals, or religious teaching. Aesir is simply a supernatural being that could not be categorized by mankind any other way. If the legends passed down in Noatun contain any truth, it was mankind itself who divided the God of Chaos into his two personalities: Loptr and Loki. Aesir bestowed upon humans free will by giving them the "Eyes of the World". This, however, also gave birth to the ideas of triumph and defeat, truth and falsehood. People awakened to feelings of hate, betrayal, jealous, and humiliation. The power of free will sparked an unstoppable surge throughout humanity that eventually led Aesir himself to wish to reclaim the power he had originally relinquished. For someone who can travel through time and space, to take back the Overseer is to control the fate of the entire world across all time. Yet, humanity's choice have sown the seeds of evil within Aesir. Whatever course of action Aesir may take can only be retribution for humanity's sin..."

Trivia

 * Aesir is referenced in Bayonetta when Temperantia explain to Bayonetta that she holds "the pride of an overseer" refering to the left eye of Aesir.