When Ouranos was killed by Kronos, his blood dripped on Gaea's soil, and as a result of that contact, the Meliai were born. Later on, they married men who lived during the Silver Age, and gave birth to the race of the Bronze Age. Eventually, they passed on and reincarnated into seven seeds.
Phillip McCaffrey, Meg's father, managed to obtain the seeds of their reincarnated lives. He intended to plant them and bring them back. However, his plans were foiled by Caligula, who destroyed the McCaffreys' home, Aeithales. Hercules, a saguaro cactus, survived the destruction of that home and hid the seeds away for safe-keeping.
Meg had a dream in which she came to know where Hercules the cactus hid the seven seeds. She planted them at the ruins of Aeithales. In spite of the hostile environment, the seeds grew into saplings at an unusually fast rate. In two days, the Meliai returned to their prime adult form. They then heard the nature song of Meg and Grover Underwood in the Burning Maze.
Teaming up with Piper, the Meliai attacked the main entrance of the maze. They forced their way through to the place where Grover, Meg, Apollo and Herophile were trapped. Piper killed Medea. Then, they all teamed up and managed to force their way to the nearest exit. Outside the exit, the Meliai killed the powerful Incitatus and all of his pandai guards.
Finally, the Meliai transplanted themselves and put their roots around the pool at the ruins of Aeithales. Their magic worked so well that Aeithales rebuilt itself in a day.
As the daughters of Ouranos and Gaea, as well as the first original dryads, the Meliai are primordial beings of great powers. They nursed Zeus himself as a baby, and helped to hide his very existence from Kronos. Joshua also once described them to be as strong as the Furies, and Apollo himself acknowledged their strength and skills as warriors.
- Chlorokinesis: As the first dryads, the Meliai possess divine authority and absolute control over plants, to a degree that is comparable to Demeter's due to their parentage. For instance, while a normal ash tree required 25 years to reach maximum height, they fully matured in just 2 days.
- Supernatural Regeneration: The Meliai possess the ability to heal at a supernatural rate - their shield rapidly healed despite being momentarily damaged by a Sun Titan's fire, and they themselves proclaimed that it would take more than that to destroy them.
- Battle Prowess: The Meliai were swift and adept warriors, effectively bringing down Incitatus and all of his pandai guards before they even had a chance to fight back.