Dwayne is an acquaintance of, and partner in crime with Alzbeta. He can be found in the Sewer Tunnels under the Crow's Nest district of Aleroth during the events of Divinity II: Flames of Vengeance. He supplies Alzbeta with food to fulfill her agreement with Sir Gula by any means necessary, including theft and cannibalism.
During the quest An Appetite For Murder, Bernard asks the Dragon Knight to investigate the disappearance of food destined for the city's poor and destitute, and the continued absence of two healers who were sent to investigate. The trail leads to the Sewer Tunnels and Dwayne. During a struggle Dwayne had killed Otto, and served his remains to Gula as a meat pie. After revealing this, Dwayne (level 39) attacks and is subsequently killed. Joramson is found imprisoned, but alive, and is saved from the same fate.
Dwayne can be mindread for 15000 exp to reveal: "So bloody annoying to have to press those secret buttons near the torches every time I want to get into the storage room!" This is a hint that the eastern gate in the Sewer Tunnels can be opened by activating levers. It is not necessary to mindread him to do so.