A nightmare being from the spirit world, the Lord of Locusts was a nightmare being who wanted to rule the world. But in order after inhabiting the body of the Queen of Dragons, Mim. Causing Mim to go insane, the other dragons stood up to their queen to face her off. It was this battle that formed the Valley and its mountains. Knowing that they could not restrain the Lord of the Locusts or their Queen, the dragons resulted in a final strike, turning their Queen into stone and trapping the Locust within her forever. But in time, even the bonds the dragons threw over him were no match.
In the adventures of Rose Harvester, it was revealed that the Locust chose a powerful dreamer, a Veni Yen Cari, called Briar Harvester to become his minions as she fell in love with him. With his help through the years, she corrupted a river dragon, Balsaad, and managed to wreak chaos across the Valley. Rose then met Balsaad in the final battle and confronted the Lord of the Locusts himself. However, he could not corrupt her and sent Balsaad to destroy her once a for all. She, however, sliced the river dragon into pieces as they fought on the river (mirroring the Lambton worm battle).
However, in order to maintain balance to the dreaming, Rose would have to kill the first person she saw... her sister, Briar. However, she instead killed her pet dog as a peace offering to the balance of the Dreaming. This was a poor mistake as the Locust would continue to be at large... and search for another Veni Yen Cari.
As time grew, the Locust commanded an army of Rat Creatures to attack the citizens of the Valley. The war ended with a treaty. But that did not stop the Lord of the Locusts at all. On the Night of Thunder, Rat Creatures demolished the old kingdom of the Valley in search of the new Veni Yen Cari, Thorn. Her grandmother, Rose, led her to the dragons to protect her from war and keep the Locusts far away from her.
But the Locust would not surrender until he was freed from his imprisonment and out to destroy the world.
Years later, a "sign" from the desert came to now nearly dead Briar Harvester. A massive election balloon of Phoncible P. Bone arrived and Briar believed that he would be a Veni Yen Cari. This angered the Locust for he wanted the powerful princess to be his vessel. But jealousy overtook Briar and convinced the Lord to capture Phoney Bone, allowing the story to begin. Sending his Locusts to capture this Bone creature, he had separated the Bone cousins, Phoney, Fone, and Smiley Bone... setting the wheels of time in motion. Though the Locusts nearly captured them, the plans were interrupted by Mim's son, the Red Dragon, bringing serious tidings to the Locust and his followers.
After when Thorn Harvester met with Fone and Phoney Bone, he sent Rat Creatures to capture Phoney. But this was thwarted by the Red Dragon and Rose Harvester. When the time came as Thorn, Rose, and Fone Bone set out for the old Kingdom of Atheia, the Rat Creatures, sent by the Locust himself, attacked Thorn. She managed to fend them off.
By the time the villagers managed to realize that the Rat Creatures and the Locusts were warring on them, Briar kidnapped Phoney Bone to ressurect the Locusts. However, it was revealed that Phoney Bone was not the Veni Yen Cari, angering the Lord of the Locusts and attempting to retake Thorn's body. However, Phoney Bone was not "an awakened one". Since there was only one Veni Yen Cari, part of the Locusts' powers escaped through a massive volcanic eruption, swallowing multiple areas of the Valley and transforming them into Ghost Circles.
Due to her second failure, the Locusts took away Briar's life a second time as punishment. After Thorn, Rose, and the Bones escaped, Briar was ressurected by his powers.
It was then realized that it was not Phoney Bone that was his Veni Yen Cari, but Fone Bone!
At last when Thorn, her grandmother, and the Bones reached Atheia, Briar led the assault on the kingdom as a reawakened Mim with the Locust within her, traveled to the kingdom to destroy it.
However, it was Fone Bone and Thorn who defeated the Locust by combining him with his polar opposite, the Crown of Horns. Briar was destroyed at long last.
Mim was freed from her bonds and Atheia was in peace... for now.
A more cruel and sininster being that does not tolerate failure. He is perhaps not a powerful spirit on the planes of the spirit world but is considered the greatest threat the world had ever known. He is shown to be manipulative and seductive to both the Harvester sisters, Rose and Briar and had capabilities to manipulate Balsaad, the river dragon.