Bosus was a member of the group of rogue Borg led by Lore.
He was part of a Borg group which attacked a Federation outpost on Ohniaka III in 2369. During a following battle with an away team from the USS Enterprise-D, a friend of Bosus named Torsus was killed. For this he swore revenge and killed Enterprise-D security officer Corelki, before Lieutenant Worf could kill him. (TNG: "Descent")
Bosus was played by Richard Gilbert-Hill.
This character was only named in the source's end credits.