Can someone give me a brief description of the role the Dianoem plays (and/or its actual history/purpose) in adventures three and four.

My group is just wrapping up Scouring and is on the road to the Fire Forest. En route, they'll meet Marben Diamondheart and his fellow dwarves. Since the Dianoem is of dwarven craftsmanship, I want Marben to drop some history regarding it, hopefully foreshadowing some of the events to come.

Help much appreciated.