Already on shaky ground following the disappointing performance of The Mummy, Universal Pictures' fledgling Dark Universe now appears to be in serious jeopardy with the departure of its chief architects.

RELATED: Alex Kurtzman's Dark Universe Future in Doubt

According to The Hollywood Reporter, writer-producers Alex Kurtzman and Chris Morgan have left the studio's "monsterverse" -- a planned shared universe featuring the Wolf Man, Dr. Jekyll & Mr. Hyde, the Bride of Frankenstein and other classic monsters -- with the former now focused on television, and the latter returning to the Fast and Furious franchise.

Kurtzman, a co-creator and executive producer of Star Trek: Discovery, seemed to signal as much in August when asked whether he was still involved with the Dark Universe. "You know the truth is, I don't know," he said at the time. "I really don't know. I haven't really decided is the honest answer." THR notes his deal with Universal expired in September.

Starring Tom Cruise, the Mummy reboot was intended to serve as the cornerstone for the long-discussed Dark Universe, which would expand in 2019 with Bride of Frankenstein, written and directed by Bill Condon (Angelina Jolie was frequently mentioned for the title role, but she's apparently not attached). That film has since lost its release date, but is reportedly still in development. Whether it will remain as part of a shared cinematic universe, however, remains to be seen.

THR reports Universal is "exploring its options," which may include finding a new architect to revamp the Dark Universe concept or approaching producers and directors with films that would effectively stand alone, unconnected to a larger universe.

Panned by critics and audiences, The Mummy boasted a production budget estimated at anywhere between $125 million and $195 million, with another $100 million or so spent on advertising. It grossed $409 million worldwide.