Osmund was a minor antagonist during Curse of the Blood Sea. A halfling rogue, he used to be a part of a party alongside D'vorah. He then betrayed him and became a spy for the Lunar Collective.
He was later rescued from a Crimson Prison and killed by D'vorah.
On the Lunar Collective mainland, he traveled with D'vorah and a few other people he made friends with. Osmund was charismatic and usually was the one who got customers since he was good at talking.
Eventually Osmund started getting cocky because of his effectiveness and realized that he had control. Traveling through some Lunar territory he being his cocky self thought he could join up with the collective and out D'vorah.
A random night five lunar soldiers showed up, but thankfully Mavros alerted D'vorah and he was able to get away- the others werent all that lucky. The Lunars made Osmund one of their informants and rewarded him, something D'vorah saw happen through the eyes of Mavros who was by a window in the Lunar complex.
Years later in 3E452, D'vorah found him in a Crimson Prison alongside Alastorm Redfield and Phaona Arrands. They rescued Osmund and took him to the Plane of Fire, but upon returning to Abmarah D'vorah killed him and took his revenge.