Stormreign leads the Guardian Knights, sworn to prevent their former mistress Quintessa from reclaiming her staff. Their ship having crashed on a secluded part of Earth, he is content for his warriors to remain hidden, far from the Great Deceiver's eyes, but the right cause—the right man—might just convince him to fight the good fight once again...
Stormreign forms part of Dragonstorm, the Knights' powerful combined form.
The Last Knight film
After betraying their supposed creator, Quintessa, Stormreign and the Guardian Knights fled with her staff to Earth, in truth the dormant form of legendary Transformer Unicron. Sometime in the late 5th century, the human "wizard" Merlin stumbled upon the knights' spaceship, buried beneath the hills of England. He met Stormreign and his men, and learned of their homeworld of Cybertron, but promised to keep their existence a secret from his peers. In 484 AD, Merlin returned to the ship and made a heartfelt plea to Stormreign, seeking aid for King Arthur and the Knights of the Round Table in a dire battle against the Saxons.
Moved by the human's words, Stormreign bestowed upon him Quintessa's staff, and dispatched Dragonstorm to fight alongside Arthur's men, winning them the day. In the battle's aftermath, the Knights of the Round Table forged an alliance with the Guardian Knights, beginning a heraldic order which would become known as the Order of the Witwiccans. On at least one occasion, Stormreign charged into battle alongside Arthur's men. Sir Edmund Burton's collection included an excerpt of the Bayeux Tapestry which appeared to show Stormreign and his knights fighting in the Battle of Hastings in 1066 AD. Eventually, the Guardian Knights moved their ship underwater and entered a centuries-long slumber, guarding Merlin's remains and the staff Stormreign had granted to him. In the modern day, the spaceship was located by Merlin's last descendant, and the knights awoke, Stormreign among them. After Quintessa successfully reclaimed her staff, intending to use it to transfer energy from Earth/Unicron into the desolate Cybertron, Stormreign and his warriors joined the Autobot mission to stop her, combining into Dragonstorm from atop the deck of the Autobot ship. As part of Dragonstorm, Stormreign helped the Knights' Autobot and human allies by taking out enemy fighters and dropping Optimus Prime into the battlefield to vanquish Infernocus. After Quintessa and Megatron were defeated and their plan was foiled, Stormreign and the Knights merged into Dragonstorm and departed Earth for Cybertron alongside the Autobots.