In Dungeons of Dredmor, your character doesn't have a "class" (or class of any sort, for that matter) -- instead, you define your abilities by choosing seven Skills. Each grants access to a variety of different abilities, such as enhancing your strength with a specific type of weapon, or the knowledge to craft things from various items found around the dungeon. As you level, you gain further abilities from each skill family, making you even more powerful.
There are 51 Skill total, and they are broken into three groups: Warrior (16), Rogue (15) and Wizard (20). For more information on what this means check out Leveling With Skill! in the attributes page.
Master of Arms
Big Game Hunter