A novel I read at least 15 years ago was about a dwarf who was visiting a human woman he had known for years. He referred to her as Sif, I think. At the time of the visit he was one of the last dwarves left. He told her about a time when dwarves were common and he was a member of a mixed group of dwarf and human fighters. A large amount of time was spent describing berserk warriors and a period in his life where he was out of control and was a berserker himself. I remember the novel was fairly short ~ 250 pages or so and was not a series. I wish I could remember more but that is it.
I've read the Dwarves books by Markus Heitz and agree that they do fit the description well. However, I also recently read the Nameless Dwarf books by D.P Prior and they have a lot of berserk dwarves in them...
For more than a thousand years, the dwarves have hidden away from the world in their ravine city of Arx Gravis. Governed by an inflexible council whose sole aim is to avoid the errors of the past, the defining virtue of their society is that nothing should ever change.
But when the Scriptorium is broken into, and Ravine Guard Carnifex Thane sees a homunculus fleeing the scene of the crime, events are set in motion that will ensure nothing will ever be the same again. Deception and death are coming to Arx Gravis. The riddles that preceded Carnifex’s birth crystalize into a horrifying fate that inexorably closes in.
But it is in blood that legends are born, and redemption is sometimes seeded in the gravest of sins. For Carnifex is destined to become the Ravine Butcher, before even that grim appellation is forever lost, along with everything that once defined him.
Markus Heitz's novel, Die Zwerge, published in English translation as The Dwarves has some element of this description.
- The protagonist is a dwarf raised by a human wizard---and was said to be the last of his clan.
- One of the (many) important characters is a Dwarf berserker--and there is a tragedy wrapped up in that tale.
I don't think its the one you are looking for however as it
- Is more than 600 pages long in trade paperback
- Features a world with five large clans of dwarves living in the mountains surrounding a large (continent sized) valley inhabited by elves and men.
There is now at least four sequels.