One year following the defeat of Drago Bludvist, the Warlords who captured dragons in an attempt to build a dragon army suffered enormous losses due to constant raids by the Dragon Riders. After accepting their most recent shipment of only one dragon, they decided to hire famed dragon hunter and slayer of Night Furies, Grimmel the Grisly, to capture Toothless, the Alpha Dragon of Berk in order to control all dragons.
When Grimmel revealed that he intended to kill Toothless himself instead of giving him to the Warlords, they soon found themselves in a battle against the Dragon Riders. They managed to hold their own very well, but soon met their fates when Ragnar is chased away by a flock of Hobgobblers and Chaghatai and Griselda are locked in a cage when two ships collapsed. Their fate remains unknown.
In the concomitant events of School of Dragons, the Warlords built a large camp on Glacier Island. While waiting for reinforcements, they were attacked by both the Dragon Riders and Nikora Stormheart's forces. However, the latter fled the battle almost as soon as they arrived and the Warlords managed to defeat the Dragon Riders with the help of Grimmel.