This is a quest that is split into two different outcomes depending on what your choice was in the previous quest, In The Shadow of Fate. This will wrap up the entire quest line and will get you the trophy for Sebastian. The guide below goes over both paths of In The Shadow of Friendship and how to complete the quest.
How to Start and Complete In The Shadow of Friendship
This is the final quest in Sebastian Sallows’ quest line, and it has two different versions depending on whether you sent Sebastian to jail or not. Once you complete In The Shadow of Fate, wait using your map, and you will receive an owl mail from either Sebastian if he’s still free or Ominis if he is not. Either way, you will need to go back to the Undercroft and speak with the character who sent you the owl mail.
Both sets of dialogue reflect on the events of using the killing curse and set the tone for how the rest of Sebastian’s life will likely go. Once you finish this conversation, you will receive the trophy for beating Sebastian’s quest line.