Avatar: The Last Airbender has only three characters who are shown bleeding. This isn’t surprising since the animated Nickelodeon show is rated TV-Y7-FV, meaning it’s geared toward young children – ages seven and older – but contains fantasy violence. The fantasy violence likely refers to the “bending” that exists in the world of Avatar. Some of the characters in Avatar can control various elements – earth, water, fire, and air - and use them in combat. Bloodbending also exists in the world of Avatar and has frightening implications, but no blood is shown when this power is used. Only one of the three characters who bleed in the series was injured by bending. The other two injuries were caused by non-mystical sources, though none of the wounds shown are graphic or excessively bloody.
Overall, Avatar is a very family-friendly show and its successor, Avatar: The Legend of Korra, maintained the TV-Y7-FV rating. Even though it was a slightly darker and more mature series, The Legend of Korra also included little to no blood. However, even the small amount of blood in both shows may have contributed a stricter rating in some countries, like Poland and South Korea. These countries specify that their content rating for children only allows bloodless violence. Whether due to blood or other objectionable material, Avatar and The Legend of Korra both received ratings more equivalent to TV-14 in a few countries. Still, Avatar shows only three characters with bloody injuries and two of the instances are very brief.
The most visible bloody wound in Avatar belongs to Prince Zuko of the Fire Nation. In Avatar: The Last Airbender season 2, episode 1, “The Avatar State”, Zuko can be seen with several scratches on his face, which he supposedly got from a fight with his sister, Azula, but this is may not be true. Zuko had the same scratch pattern on his face for the three previous episodes, beginning in season 1, episode 18, “The Waterbending Master”. Commander Zhao of the Fire Nation Army plots to assassinate Zuko with the help of some pirates, who then blow up Zuko’s ship. Zuko survives, and the next time he's seen, he's in disguise on Zhao’s ship. When he removes the mask covering his face, the scratches on his forehead, lip, cheek, and nose are revealed. Enough time had passed since the explosion for Zuko to find Iroh, concoct a plan, and find a uniform to disguise himself. So, by the time viewers see Zuko’s wounds, it’s likely that they had stopped bleeding, but could have still been fresh enough to appear bloody.
Later in the series, Aang is shown with a similar injury he received from Azula, a powerful firebender. Aang’s wounded foot in the season 2 finale, “The Guru / The Crossroads of Destiny”, looks a lot like Zuko’s scratches - red, yet not dripping with blood. As Aang enters the Avatar state and floats into the air, Azula strikes Aang with lightning. A star-shaped wound can be seen on the bottom of Aang’s foot as he falls to the ground. The wound is fresh and would likely be bloody even if it weren’t bleeding profusely.
Of the three Avatar characters who are shown with bloody injuries, only Appa has blood visibly pouring out of his wound. The first and most "graphic" instance of blood in Avatar occurs in season 2, episode 15, “Appa’s Lost Days”, when Appa, Aang's lovable sky bison, fights a wild boar. During the fight, Appa rolls through some large, thorny plants. After the boar runs away, Appa plucks one of the thorns from his shoulder, a small amount of blood splashes out of the wound, and Appa roars in pain. It’s a brief, darkly lit scene, but Appa definitely bleeds.
Despite the fact that Avatar’s central conflict is a global war, the show generally depicts violence in a non-graphic manner, but that doesn’t mean that Avatar is wholly lighthearted. Avatar is indeed a children’s cartoon and, as such, contains little objectionable material, but the themes of war, friendship, trauma, and healing are universally relatable, making Avatar: The Last Airbender appealing to fans of all ages.