Not much is known about the Warlords other than they have taken over Drago's Army following their leader, Drago Bludvist's defeat one year ago. Having problems with the Berkian Dragon Riders, who mess with all their operations, they hire the renowned dragon hunter Grimmel the Grisly to capture Toothless so they can use the Night Fury to control all other dragons, and conquer the world through it.
The Warlords are first seen discussing their plans with Grimmel. Later on, they are seen after the Berkians evacuated Berk, having found the island empty and destroyed following Grimmel's attack the previous night, where his Deathgrippers burned the town. Griselda asks Grimmel how Toothless could have escaped once again, and Grimmel reveals that he discovered that the Berkians are heading west. He then explains his plan to capture all the dragons, though they're not amused by Grimmel's twisted sense of humor.
Soon after Grimmel is able to capture both Toothless and the Light Fury, he brings them over to the Warlords. However, he betrays them by revealing that he was never going to let them have Toothless and he was planning to kill him all along, and the Warlords realize they were betrayed by Grimmel. However, the Dragon Riders came to rescue Toothless, and Eret, Valka, and Gobber confront the Warlords. Astrid manages to make two of the ships collide, causing the Warlords to be trapped in a cage. What happens to the Warlords afterwards is unknown, but it can be deduced that any of their men could have released them from the cage and escape aboard one of their ships (if any of their ships survived the ambush), but if not, it's likely that the ship with the cage aboard eventually sunk, dragging the Warlords inside the cage to the depths of the ocean where they would drown.
Ragnar the Rock (current leader and former second-in-command of Drago Bludvist)
Griselda the Grievous (current second-in-command and former third-in-command of Drago Bludvist)
Chaghatai Khan (current third-in-command & former fourth-in-command of Drago Bludvist)
The Warlords are believed to be the secondary antagonists of the film behind Grimmel the Grisly, who represents the main threat to Hiccup and the Berkian Dragon Riders. However, this is untrue, as Grimmel's Deathgrippers served as Grimmel's henchmen and a dangerous threat due to their drugged state whereas the Warlords just had their men to defend themselves.
Ragnar the Rock's voice actor, Ólafur Darri Ólafsson also did the portrayal of Belial from the 2015 supernatural action film The Last Witch Hunter.
Ragnar the Rock is a reference to the Norse doomsday term "Ragnarok".
Unlike other characters from the How to Train Your Dragon franchise, the Warlords lack a unique body model. As revealed in the film commentary of How to Train Your Dragon: The Hidden World, their bodies were replicas of those of Eret (Chaghatai Khan), Stoick (Ragnar the Rock) and Valka (Griselda the Grievous) with different costumes. This had to be done due to time constraints during the third film's development.
Ironically, Ragnar the Rock was voiced by Ólafur Darri Ólafsson, the Icelandic actor who previously dubbed Stoick the Vast's voice in the Icelandic dub of the first and second films.