2 Song of Seas and Flames » by CyberActors15 Two children with the power of gods and the ability to alter destinies and a world divided by war. The Gods, Poseidon and Hades, have both decided to send young children to the World of the Avatar where they can be safe from the fury of Zeus. But the gods failed to account for the ongoing war. The children will be safe from the thunderer but they aren't safe from War.

12 A Hero between Two Worlds » by XifosGladius (AU) Monsters, evil beasts, calamities capable of destroying civilizations, the fate of two worlds and only one hero is able to decide, his name is Percy Jackson, raised by the fire lord Iroh in a world full of dangers and without an avatar, while The gods of Olympus desperately seek him to support them in a battle against one of the most feared enemies, Kronos.

25 Avatar La Leyenda de Perseo » by JkAlex Un semidiós ha sido enviado a un mundo donde los mortales tienen la habilidad de controlar los elementos. Un mundo que ha estado en guerra por cien años. Un mundo que necesita desesperadamente un salvador. ¿Qué sucederá cuando un hijo de Poseidón llegue a las Cuatro Naciones? ¿Será su salvador? ¿O será el heraldo de un futuro mucho más oscuro? Crossover entre Percy Jackson y Avatar

10 All The Time In The World » by Cheesecake1010 Gaia has won. With Olympus shattered and the Underworld overwhelmed, Earth teeters on the brink of destruction. Hestia and Hecate offer a final hope: a device forged from Kronos's scythe, leading Percy, Annabeth, and Nico to a mysterious world of spirits, elemental masters, and an Avatar fighting to restore balance. The fate of both worlds rests on their shoulders.

134 Storms and Monsters » by maroooon "I don't bend the water. I command it. It listens to me." Percy never thought he'd become a universe-hopping one-man army capable of destabilizing a whole country. But Katara believed in him. That had to count for something, right?

52 To Storm or to Fire » by Manke Exiled for his crimes, Percy finds himself living a new life in the world of bending. Loyal to the Fire Lord, he stands guard to the kingdom's elite. However, his dreams are plagued by a simple demand: find the avatar.

14 Percy Jackson and the Suspicious Lack of the Periodic Table » by Just.a.violist Percy somehow ends up in the world of Avatar. Not entirely clear how or why yet. Now all he wants is to get back home and see Annabeth again. And maybe he'll save some people along the way. He tends to do that.

6 The Way of the Water » by Le Connoisseur The wrong shall be righted. Balance shall be restored. Dreams and hopes, cleansed from the soul.

11 Rider On The Storm » by darthwizard Percy Jackson awoke in the middle of the storm, deep below the ocean, with no memory as to why he was there. He was saved, by a strange Prince with a nasty scar and his Uncle. What happens next is the greatest adventure of his life. He will fight to save this world from being destroyed by the Titans, but first, he must find the Avatar!

12 Waterbender of the Fire Nation by savagegooser Story for mnp16891, someone tell him to stop, I am going to cry. Percy wakes up in Omashu with no idea what is going on. Follow him as he makes alliances and explores this new world. Eventually Percy x Azula.

9 Alexander Cain: World at War » by Death Fury Alex was not your normal demigod, even by demigod standards. Throw into the mix the fact that he was the gods' Champion things were never easy for him. Though with his missions complete and oaths fulfilled. Chaos sends him to another world where there are no gods where he can have a more normal life, but there is a catch. The World is at War and he must help bring Peace and Balance

1 Shadow and Sunshine in Benderland » by Dolbez Nico and Will finally get a bit of reprieve from the truly big quests for a few months. Then they are sent off again.

31 The Boy Who Fell from the Sky » by memorykey3 Sent on a mission the second he gets back from Camp Half Blood, Percy is more than a little confused when he ends up in a war in an entirely different world. In order to get back home, he will need to put an end to the war and restore balance to the Avatar universe.