Following Ozai's defeat, Zuko is crowned Fire Lord, and he begins to help the world rebuild. Aang begins to wear traditional Air Nomad monk clothing, Katara and Sokka are reunited with their father, Katara and Aang finally become a couple, Toph reunites with The Hippo and The Boulder, Mai and Ty Lee are released from prison and Zuko and Mai become a couple again while Ty Lee joins the Kyoshi Warriors, Iroh reopens his tea shop in Ba Sing Se, Ozai loses his Firebending and is put in the capital city prison, and Azula is taken to a mental health institution (as stated by Nick.com). Zuko also finds out the fate his mother, though it is not stated on-screen, nor is she shown.
When Suki is reaching out for Sokka's hand while her airship descends, the yellow lining on her belt is gone.
When Aang stands on stage, before we see Katara, his sash is yellow but the dangling part is still red.
When Katara and Azula are waiting to attack at the grate, a door can be seen at the end of the hallway-like structure around them, but when Azula rolls to dodge Katara's attack, the door is missing and the coronation temple is enlarged.
When Katara falls onto the grate, the waterskin strap that stretches from right shoulder to left hip is colored white like her collar.
When Ozai leans in to check if Aang is alive or not and Aang grabs his goatee, his red hairband turns brown like his hair.
While Aang is seeing his past lives, an Air Avatar with a droopy whiskery mustache, a stubby goatee, and a drape over his left shoulder can be seen following a female Fire Avatar, but later on when the same Air Avatar appears once more, a male Fire Avatar with a large hat appears before the Air Avatar instead.
Before we see Suki's return, Sokka is seen frowning and clutching his leg, during which his eyebrows are colored like his skin.
While Zuko criticizes Sokka's drawing, Katara's hair is missing from between her side and left arm.
Zuko's topknot band changes from red to orange at random points in his coronation.
The top gold ring on Zuko's topknot band continuously disappears and reappears throughout his coronation.
Ty Lee says that she and the Kyoshi Warriors had bonded in prison, yet Suki stated that she had been sent to the Boiling Rock alone, and Mai and Ty Lee were also held at the Boiling Rock, so they couldn't have interacted with the other Kyoshi Warriors.
This episode and series ends with a title card saying "The End" in Chinese.
Zuko gets a scar on his lower chest, in the exact same place as the one on Aang's back.
When Zuko is asking Katara what she thinks will happen, her fingers are blue.
When Jeong Jeong is fighting against the Fire Nation tanks, he shoots a wall of fire at the tanks moving them out of the way. In the next scene, they are back where they were before.
Into the Inferno is also the title of the third Avatar: The Last Airbender video game that was released in October 2008.
Since both Bumi and the guards stared at the eclipse they should of gone blind or at least suffered severe retinal burning. However, Bumi was fine.
It is revealed that the female face that was seen on Koh the Facestealer in "The Siege of the North (1)" was Avatar Kuruk's love interest, Ummi. However, this was also revealed in the online game/web episode, "Escape from the Spirit World".
The smell sample which Zuko presents June is the sandal which Iroh intentionally drops during the events of the season 1 episode The Spirit World (Winter Solstice, Part 1).