In Dungeon Siege III, 150 years have passed since the ending of the original Dungeon Siege. Some 30 years ago, a woman named Jeyne Kassynder led the rebellion and took over the power in the fantasy realm of Ehb. Kassynder framed the heroic 10th Legion, featured in Dungeon Siege, for the murder of the king, and nearly annihilated them.
The player takes the role of an heir to one of the last surviving Legion members. There are four possible protagonists with pre-scripted backstories to choose from, and the main plot will slightly differ based on your choice. However, regardless of which character you choose, the other three will eventually appear in the game and can be recruited to accompany the player, one at a time.
Each character has his or her unique set of skills and attacks. For example, Lucas, a knight, can withstand heavy damage in a melee fight. Katarina prefers ranged weapons and a little magic. Anjali is a shape-shifter who is a combination of both, depending on her current form, and Reinhart is a classic magician who uses energy spells. The controls are very different from the previous parts: the point-and-click approach was scrapped in favor of arrow keys and attack buttons.