Legendarygender, or legendarypokegender, is non-binary xenogender relating to legendary Pokémon. This can be any legendary, for example, Mewtwo, Zygarde, Giratina, etc. One may feel they are multiple legendaries or only one. They also may feel like a sub-legendary Pokémon or a mythical Pokémon. This falls under the xenogender, kingender, and pokémongender umbrella however one does not have to be kingender to use this term.
Flag
The red, green, and blue stripes represent the 3 starter types, fire, grass, and water. The golden star and stripe is to represent being a sub-legendary/legendary/mythic.