Cro is one of the base metals from the alloy alignment system based on chromium. It represents a gender that, to some degree, can only be defined by the individual themselves. Only the individual with the gender themselves can express, experience, or perceive the gender. It is too unique to be shared or understood by others. It is similar to egogender. These are for the genderhoarders, self-defined gender experiences, and others who choose to break gender norms. How one expresses or experiences their gender is defined by them. A cro individual can have any alignment or presentation.
The original alloy alignment system was coined on December 1, 2018 by Hail, the original owner of the Tumblr blog lgbt-alchemy. The term cro, however, was not in this original version of the system. Cro was coined on December 19, 2019 by Tired, the new owner of the blog, in a rework of the system.
The flag is based on the color of chromium alloys. The symbol used is the alchemical symbol for chromium.