The remains of the Manor can be visited
Demmin Manor

In Mecklenburg-Vorpommern, Haus Demmin comprises the ruins of an ancient princely castle and a former manor house. This site, on an island at the confluence of the Peene and Tollense rivers, dates from Slavic settlements to noble ownership and destructions.
History+
The origins of Haus Demmin date back to the 8th century, when a Slavic fortified settlement existed here. First documented in 1127 as the 'Old Castle,' it served as an overnight stay for Bishop Otto of Bamberg a year later. In the 12th century, the castle was further expanded and documented in 1170 as Feste Demmin. The oldest preserved secular building in Pomerania, a brick round keep, dates to around 1200. Until 1264, Haus Demmin was the residence of the Dukes of Pomerania-Demmin and later, from 1295, part of Pomerania-Stettin. It functioned as the seat of a ducal bailiwick and a customs post. In the 16th century, the castle became a fiefdom of the Podewils family.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: https://commons.wikimedia.org/wiki/File:Haus_Demmin_09.jpg
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 53.9000, 13.0336