We rated the five most powerful animals in Avatar: The Last Airbender.

In Avatar: The Last Airbender, the most powerful creatures are defined by more than just brute strength. The Nickelodeon Animation Studio series ranks among its most powerful characters in terms of ability, size and flexibility. Its world is filled with fictional animals and hybrids of real-life species, some large enough to carry an entire island on their backs; others are tasked with teaching humans about competition.

Lion turtles are the oldest sources of bending ability.

The lion tortoise is the earliest known animal in the world of Avatar: The Last Airbender. It is large enough to accommodate an entire city on its back and can survive for centuries if not damaged, developing shells that make it difficult for plant and animal species to maintain.

Their significance goes beyond their size. Lion Turtles gave humans the ability to bend elements for the first time. They can also manipulate energy itself.

Dragons had the power to control fire.

Dragons are so terrifying because they showed the first Avatar a real way to control fire. Ran and Shaw were two ancient dragons associated with this legacy: They could burn, and their shells made them resistant to both fire and explosion, but not completely invulnerable.

Dragons are also intelligent creatures that can communicate and form bonds with humans. Roku's dragon has chosen to protect the Avatar until death. Their speed and ability to rotate during flight gives them an advantage over most other animals, and their immense size may even be a threat.

In the Serpent's Pass, the snake was a top predator.

As Team Avatar crosses the Serpent's Pass, they are confronted by a giant water monster intent on taking their lives. The snake is over 100 feet long and possesses fierce flowers, red eyes and huge teeth.

These traits make the giant sea snake one of the most dangerous animals in Avatar: The Last Airbender -- a top predator that can sink an entire ship, attack and eat almost anything, and you need all of Team Avatar to fight it.

The Unagi River blocks the waters near Koshi Island

Unagi is another fearsome and huge sea creature that threatens Team Avatar near the Kyoshi Islands. Aang was first attacked while playing with an elephant koi, a giant carnivorous eel capable of firing large water cannons from its mouth.

The Unagi is a major threat due to its large size, ferocity and powerful jets. It can move quickly; Team Avatar has only been able to control the unagi to some extent if they have never lost it.

Shirshu turns scent into a weapon.

Shirshu is a top tracker who first appears as June's loyal creature and is used to track the scents of her bounty-hunting targets. In one episode, Jon rides his shirshu Nyla onto Prince Zuko's ship.

Shirshu can track odors with terrifying accuracy using mole-like facial expressions, sense even through scent and detect a target hundreds of kilometers away. Its long, bear-like tongue is harmless and potentially lethal as it can maim prey from afar. Its ease of movement and ability to travel great distances make it one of the most powerful and hardy creatures in Avatar: The Last Airbender.

The characters and creatures in the story continue Aang's quest.

The series follows a world of elemental magic ravaged by war, where a young man awakens and undertakes a perilous quest to fulfill his destiny as an Avatar and bring peace to the world. It depicts bending, travel, and conflict because it matters in the Inventory of Beasts: lion turtles determine the origins of bending; dragons teach the true form of controlling fire; snakes and unagi threaten waterways; shirshu transforms tracking into a hunting tool.