Aethergender is a xenogender that is described as being wide, commanding, breathtaking and powerful.
Flag
Yellow and green were chosen because they are associated with being non-binary. Grey was chosen to represent wideness as well as a lack of breath. The cutoff circle was chosen because it goes beyond the confines of the flag itself. The lighter grey represents an “aura” to go with the “commanding and powerful” parts of the definition.