Durmand [Historian] is a human NPC located in the major port towns of all three campaigns. He offers access to the Missions from the Bonus Mission Pack by providing you with copies of their stories. You can access these missions by double clicking the story in your inventory and skipping past the table of contents and clicking the enter mission button. After completing any mission you can exchange your copy of the completed story for an Authorized version. These authorized versions of the stories can be traded to Diane (Saul's Story), Akemi (Togo's Story), Archivist of Whispers (Turai's Story), or Tuomas (Gwen's Story) for exclusive weapons. After completing a mission once you can go through the mission again to complete discoveries which are akin to bonus objectives in regular missions. By completing the discoveries you can obtain more authorized copies by selecting the "I have made some discoveries" option when you first talk to Durmand, and then selecting to acquire an authorized version of their story.