Xynthvir is a singular gender identity, just like female, male, juxera, etc. It is a gender that, like proxvir, is derived but distinctly separate from manhood and masculinity. In the case of xynthvir, however, it is not just derived from masculinity; it is also derived from xeninity. Xynthvir is a single gender that is derived from both masculinity and xeninity, but is a single gender, not a mix of the two, and is still completely unrelated to how xenine people and masculine people experience their (respective) xeninity and masculinity.
Xynthvir is not a combination of masculine and xenine (xensculine), nor does it describe someone who is multigender who is both miaspec and xiaspec or has xenogenders. It is a distinctly separate gender from the two: derived from them but experienced as a singular, completely coalesced gender that relates heavily to qualities of masculinity described in an entirely non-standard xenine way. That experience is core to the gender but is still separate from "standard" masculinity and xeninity.
It's important to note that xynthvir is a gender, not a gender identity, alignment, modality, etc. Someone who is xynthvir would say "I am xynthvir" or "I am xynthvirine", not "I am a xynthvir". Someone can be aligned with being xynthvir, but it is not in and of itself an alignment, as it's a complete gender, not just an alignment or quality. Since xynthvir is derived yet fully separate and distinct from masculinity and xeninity, xynthvir people may or may not identify as miaspec and/or xiaspec.
The feminine version of xynthvir is xynthera, and the androgynous version of xynthvir is xynthari.
Sun Symbol
The symbol for xynthvir people is the sun because, in nature and in many cultures, the sun is portrayed as being derived from masculine aspects and qualities, but it is still entirely separate from masculinity in a way that connects the gender experience to non-standard xeninity, making the sun the perfect symbol for xynthvir people.
History
The term xynthvir was coined by FANDOM user Reign of the queerios on a blog post on March 11, 2021, along with its feminine and androgyne counterparts.