Khun Aguero Agnis/History

Background
Not much of Koon's history is known, other than the fact he was once a member of the Koon Family.

When he was 10 years old, he took part in the yearly "official fights" where its participants are 10 year old children from the Koon branch families. The fights are inhuman and bloody and he emerged as one of the winners. As a winner, he was allowed to wear the crest of the Koon Family while the losers were abandoned.

He was later expelled from the Koon Family, due to the failure of his older sister to become a  Princess of Zahard.

At one point his attention was captivated by Maria, who was kind and altruistic, things that seemed surreal and incomprehensible to him. He felt she deserved the power and prestige of a princess, and manipulated events to make her a princess by usurping his own sister. However, ever since then he felt lonely, and didn't know that he felt lonely until he saw Baam's resolve to go up with Rachel.

After his expulsion, he was sent to the Floor of Test as a Regular. Before this happened, he raided his dad's treasure hoard and stole equipment.

Tower of God: Part 2 - The Return of the Prince
In a spoiler posted by SIU, Koon confessed to  Leesoo that he felt great sadness over Baam's death. He suspected foul play during the Submerged Fish Hunt and now wishes to avenge Baam, stating that the others were tools for this purpose. He splits the group into two: one to climb quickly and attract attention and the other to follow safely in their wake. The spoiler ends with Koon wondering why only Baam was targeted and not Rachel.

In Part II, Koon seemed to be called A.A (Aguero Agnis), a nickname used by Ran. He was seen sitting on a chair in a throne-like manner, and was wearing summer clothes and a sun-hat.

Epilogue, Path
Koon informed Leesoo that he was at the 29th Floor, and he was eager to meet up.

Prologue
Koon Aguero Agnis/Historia