Zenimax Media, parent company of Bethesda, has threatened legal action against DoomRL, a free Doom roguelike inspired by the popular FPS.

DoomRL co-creator Kornel Kisielewicz broke the news on Twitter by sharing an email (shown below) sent by Zenimax.

The email states that DoomRL is intentionally seeking to attract users using a Zenimax trademark, and asks that all such trademarks and references to the IP be pulled immediately.

"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," reads the letter. "Further legal action may be pursued if this situation is not immediately resolved."

Given the nature of DoomRL, the email effectively marks the beginning of the end for the roguelike (as we know it). As Kisielewicz explained to his followers, removing all references to the Doom brand isn't as straight forward as it might seem.

"The whole thing isn't that easy. Replace monster names? Sprites?" he wrote on Twitter. "Short version: we're fucked. 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."

Kisielewicz is currently working on a spiritual successor to DoomRL called Jupiter Hell. It's possible that Jupiter Hell's Kickstarter campaign, which has currently raised £36,135 of its £60,000 goal, caught the eye of Zenimax, which then turned its attention to DoomRL.