My primary source at the time of posting was a sentence in the Wikipedia[1] but I have added the link to the trademark[2] that was provided by Kichae and rephrased my text now.

Thank you for reminding me that I should always properly check my sources and provide all information.

[1] https://en.wikipedia.org/w/index.php?title=Dungeon_Master&oldid=1185015796 [2] https://trademarks.justia.com/742/64/dungeon-74264094.html