Zenimax Media, Bethesda's parent company, has threatened fan-made DoomRL, a Doom-themed roguelike with elements inspired by the popular FPS, with legal action.
DoomRL co-creator Kornel Kisielewicz broke the news to Twitter, also sharing the cease and desist letter sent by Zenimax.
"We demand you immediately remove all Zenimax trademarks from meta tags, keywords, media, and other visible or concealed set are are connected to your website," states the email. "Further legal action may be pursued if this situation is not immediately resolved."
Zenimax allege that DoomRL is intentionally seeking to gain popularity off the back of a Zenimax trademark, and has asked for all trademarks to be removed. This isn't as easy as it might look though, as this would require sprites and monster names to be replaced, something that probably just isn't going to happen.
"Short version: we're fucked." said Kornel Kisielewicz on Twitter. It's a lost case, I knew it would happen some day. Right now all I can do is try to get the word out instead of silently taking the site down."
This effectively marks the end of DoomRL. The last update for the game was released back in 2013 and the development company behind it is now actively pushing its new title Jupiter Hell, currently in the middle of a Kickstarter campaign. The company also did some work on an Aliens roguelike, although develop ceased on that one even further into the past.