[How do the Yun reproduce?]

1 hour ago, SinNoAria said:

There are a lot of stories (including mythology/folklore) where crossmating is possible, but where the females/males of one race would always result in a specific result.

Yes, that's all very nice but without an established lore you can't just assume different species can mate. Halfings exist in other fantasy worlds because we're told they exist. You don't just see a Lyn and a Gon and assume they can have children together...

[How do the Yun reproduce?]

2 hours ago, Teisho said:

Is there any reason to believe that they can't simply mate with other races and produce other Yun?

Yes an no. If you took "race" literally then crossmating can occur but most MMOs use the term "race" when they actually mean "species" and crossmating cannot naturally occur between species.