After nearly a decade of drawing in moviegoers through the simple appeal of seeing giant robots turn into vehicles and beat each other up, the Transformers movie series is looking to add something extra to the excitement for its fifth installment. Recent reports indicate that Transformers: The Last Knight will incorporate the legend of King Arthur into the story, to the point that an actor has already in talks to play the once and future king. Mixing medieval fantasy sounds like a weird idea at first, but actually, The Last Knight may have gotten the idea from the franchise's TV past.
As THR noted, the Transformers mythology already has some similarities to the King Arthur lore, from the Matrix of Leadership (the artifact carried by the leader of the Autobots) sharing similarities with the Holy Grail to Optimus Prime surrounding himself with other Autobot warriors to aid and advise him, much like Arthur with the Knights of the Round Table. However, it was the 1980s Transformers animated series that directly tied into the Arthurian legend with the episode "A Decepticon Raider in King Arthur's Court." That adventure saw several members of both the Autobots and Decepticons ending up in the year 543 A.D. thanks to a mysterious cave. There they met figures clearly from the King Arthur lore, but given different names. For instance, instead of Arthur, the ruler was named Aethling the Red. Regardless, the Autobots heroes helped this king and his forces defend the land from the scheming Deceptions and their scheming wizard ally Beorht (Mordred, anyone), and by the end of the episode, they were all back in the good 'ol 1980s.
While it's certainly possible that Transformers: The Last Knight was inspired by this TV episode, it's extremely doubtful it will resemble it in any way. Even though the fifth movie does appear to be shooting scenes set in medieval times, it's still going to be primarily set in the present day, as evidenced by the return of several contemporary characters. The best guess at the moment is that The Last Knight will contain a flashback showing how King Arthur and his court are connected to the robots in disguise.
Whatever ends up happening, it does look like Transformers: The Last Knight is jumping into the deep end of the Arthurian pool. Liam Garrigan is already being eyed to play King Arthur, a role he has already played in the ABC series Once Upon a Time. Santiago Cabrera has also reportedly been cast as Merlin, which is somewhat fitting since he played Lancelot in the Merlin TV series. One rumor stated that Merlin received his magic powers from a Transformer centuries ago, and in the present day, Optimus Prime and the Autobots will look for an artifact on Earth connected to Merlin that can bring Cybertron back to life. If technology can't get the job done, magic may be the only way to restore their home planet.
Transformers: The Last Knight hits theaters on June 23, 2017.