How is Dark Messiah connected to Heroes of Might and Magic?

Everything is clear with Nicolas...
But I'm still worried about Xana, specifically her origins...
Agrail couldn't possibly have agreed to Biaura...
Flirting is one thing... but physical intimacy is something else entirely!
Agrail understood that such behavior is natural for a Succubus like Biaura!
But to actually... fall for it...
That doesn't seem like him...
And in general... don't you think that the heroes, in our opinion, resemble a Brazilian soap opera more than a historical saga...?