The most powerful magi to be exiled during Hawthorne II's reign. The Five are really Four -- Erika Redmark, Patrick, Rone, and Solberg. However, due to the sometimes inclusion of Aimee or Linda in their number, they have traditionally been referred to as the Five.
The Five were exiled during a power struggle among the mages during Hawthorne II's time as Emperor. They struggled against Garzahd and a group of his students for control of the Empire's magical policy. They lost, and Garzahd became Hawthorne II's closest advisor. He urged the Emperor to Exile these dangerous mages, which he did. Before they were Exiled, Garzahd placed a powerful curse on their leader, Erika Redmark (see Banishing of the Archmagi). Erika, Patrick, and Rone were exiled together, followed shortly by the individual exiles of Aimee, Solberg, and Linda.
The Five made it their goal to make Exile a habitable place and are credited with the invention of quick-growing mushrooms, cavewood trees, and other important advances that enabled the exiles to survive where the First Expedition could not. The Five also established the Tower of Magi and served as some of the first members of the Triad. The Five led the fight to imprison Grah-Hoth in Skarragath, beat back Sss-Thoss and his demon-worshipping sliths, and helped Micah become King. (Aimee and Linda, though present and working to aid Avernum, played relatively small roles in these events.)