If you think about it, it’s almost canonically implied that Kaider’s children would also be good looking based on Kai and Cinder’s lineage. In Fairest, along with calling him handsome, Channary says “With my grace and [Rikan’s] structure, we would produce heirs so stunning the Eartheners would weep. It’s practically a biological necessity.”
When you consider that (canonically) Cinder resembles Channary, and Kai is widely deemed as handsome (and presumably also resembles Rikan), we can come to the conclusion that — at least to Channary — Kai and Cinder’s heirs would be “so stunning Eartheners would weep”













