Playing as the Legions (Disciples 2).

I always took the Duke (isn't he the archer?)

The archer is the Advisor. He's like a winged barrel with an annoying voice. But the shooting animation is great.

a gargoyle and a couple of imps

And where do you put the Incubus with the hero? In the background as a supporting unit? O_o

I remember, at one time, I liked running around with a support demon, a gargoyle, and a warrior. For variety, I developed the support demon's single-target damage, and I took the Overlord (fire damage). I don't really like Tiamat - he's too scary.
I played with the Doppelganger for a bit, but got tired of it. Usually, nothing is cooler than the Archdevil, and for dragons, an Incubus or Succubus helps better. But the Succubus has lower accuracy, and while a Fiend can hit hard, a Stone Golem won't do anything.