Koba (previously known as Kopa) is one of the base metals from the alloy alignment system based on cobalt. It represents a gender that is, to some degree, atrinary in nature. It's a gender that is itself outside any the gender binary, or trinary. It is unrelated to any idea of masculine, feminine, or neutral. It's an independent gender defined solely by the individual, not by any alignment. Examples include abinary, atrinary, maverique, and similar ideas. How one expresses or experiences their gender is defined by them. A koba individual can have any alignment or presentation.
Koba was originally coined on December 1, 2018 by Hail, the original owner of the Tumblr blog lgbt-alchemy. At the time it is was called known as kopa and the plural form was kopalt. On December 19, 2019 the alloy alignment system was reworked by Tired, the new owner of the blog. In this rework the name of the term was change to koba. It's unknown what the plural form of the new term would be.
The flag is based on the color of cobalt. The symbol used is the first alchemical symbol for cobalt. The reason cobalt was chosen is because cobalt is a unique metal that looks unlike any other metals.