It is prequel to Divine Divinty, but I'm having hard troubles to understand how "original Sin" related to Orc swarm. IIRC, the Story.pdf from DD pretty clearly states that all the races were against Damian's invasion, Orcs as well.
Damian didn't exist until DD. Why would an alliance against a common enemy necessarily mean that races would forever after remain on good terms?
Seems like they had to introduce another "deus ex" element, ehh. Kind of sad (and weak), but oh well...
The DD pre-story described an attack by the Lord of Chaos 600 years before DD. Original Sin is set 200 years before DD.
