A bunch of Slightly Damned fan characters doing a bunch of breeding-related hijinks.

Mitten and Tabris are Angel siblings raised on Medius. First Attempt is Mitten's creation, a prototype Angel/Demon Mixling. Razuka is Tabris' Demon boygirlfriend. Faust and his packmates are Demon soldiers.

If you want all the lore and (sfw) story details, it's over there.