After Weylin's assassination attempt on Margret, an Imperial operative, the Dragonborn searched his room for evidence on a motive. Learning that Weylin was employed by a mysterious person named "N", they exit the Warrens, only to be confronted by Dryston, who is angered by the Dragonborn's sleuth-work.
If the Dragonborn wins the brawl against him and doesn't kill him, he will reside in Weylin's room in the Warrens afterwards.
- May appear as a radiant target for the Thieves Guild quest The Fishing Job - Note: If The Forsworn Conspiracy has not been started, the Dragonborn will find a quest arrow where Dryston should be, but the NPC will be nowhere to be found, resulting in the Dragonborn being unable to complete this quest. Simply returning to Delvin and quitting will allow the Dragonborn to start again with a new target.