One of the highlights of “The Legend of Korra” is seeing the original “Avatar: The Last Airbender” characters later in life. Katara becomes a revered elder of the Southern Water Tribe and helps Korra heal both mentally and physically from her traumatic experiences with Amon, Unalaq, and Zaheer. Toph grumbles her way into Season 4 just in time to help save her children and grandchildren from a fascist earthbending regime, and Zuko gets to ride a dragon in one of the greatest character entrances ever. Sadly, though, Sokka is not among the characters who return in “Korra,” and the sequel series makes it clear early on that he died some years earlier.

For many “Airbender” fans, that was a tough pill to swallow. Aang’s death was a given since Korra’s mere existence requires his reincarnation, but since most of the other younger characters from the original show are still alive 70-odd years later, it seemed especially sad that Sokka wasn’t among them. Longevity is generally greater in the “Avatar” universe than in the real world, with particularly powerful individuals living incredibly long lives. Avatar Kyoshi, for instance, canonically died at the age of 230.

Sokka is the glue of the original Team Avatar. He’s the comic relief, the boomerang guy, and the one who always has a plan. He proves that even in a magical world, those without bending can be just as valuable to the cause. And to this day, we still don’t know how Sokka died, but there are some major theories. Let’s get into it.

There are a number of canonical “Avatar: The Last Airbender” comics that take place after the end of Season 3, and Sokka features prominently in several of them. These arcs take place in the years immediately following the show, so the characters are a bit older but still similar in age to their TV counterparts.

In “The Promise,” the first of the “Airbender” comics set after the series, Sokka helps Aang, Katara, and the rest of the gang deal with a mounting conflict in a Fire Nation colony that’s lingered on Earth Kingdom land after the war. He helps Toph start up her first metalbending academy and later joins the gang (plus Azula) on a quest to help Zuko find his long-lost mother — a quest that ends successfully.

After that and another brief encounter with an angered spirit that Aang faces off against, Sokka and Katara return home to discover the South Pole in the midst of a massive reconstruction effort. Urbanization and industrialization campaigns, headed up by Northern Water Tribe members, revitalize the South but also rekindle some inter-tribe animosity, as a group of Southern nationalists reject any sort of Northern occupation. In the end, Hakoda, Sokka and Katara’s father, is named the new formal chief of the Southern Water Tribe. In the “Imbalance” arc, Sokka helps Suki — who he keeps dating throughout the comics — train a group of non-benders being oppressed by a bending ruling class in Cranefish Town.

“Korra” reveals that Sokka later served as the Southern Water Tribe’s representative on the United Republic Council, and sometime after that, he served as chief of the tribe.

In “The Legend of Korra” Season 3, we learn about the Red Lotus, an extremist group that tried to kidnap Korra as a baby and raise the new Avatar as one of their own. When they return in her adulthood, Tenzin tells Korra what happened in the past and says that “Chief Sokka” was a part of the group that helped defeat and capture the Red Lotus back then. This tells us two things: Sokka outlived Aang, and he was Chief of the Northern Water Tribe during Korra’s lifetime.

Since Sokka dies relatively young compared to the other characters, one longstanding fan theory is that his battle with Zaheer and the other Red Lotus members somehow played a role. It seems unlikely that the Red Lotus actually killed him, as that would probably be relative information in Season 3, and no one makes the claim. However, some fans still suspect that the battle itself contributed to Sokka’s premature death.

In reality, we just don’t know. It’s possible that Sokka died of natural causes, or, alternatively, that some other dangerous situation came up after the Red Lotus members were captured. With Avatar Studios working on tons of new stories, we might eventually learn what really happened to Sokka, and there’s definitely room in the “Avatar: The Last Airbender” timeline to slide in another adventure between Korra’s infancy and his death.

Any time a beloved character dies off-screen, the fans are going to wonder. The mystery of Sokka’s death has been a point of focus in the “Avatar: The Last Airbender” community for years because it’s one of the big plot points for the original cast that remains unknown. It’s right up there with other lingering questions, like what happened to Suki, and who’s the mother of Zuko’s daughter, Izumi (two questions that might have the same answer).

Because he’s such a popular character, and because he plays such a crucial role in world affairs throughout his life, many fans have a hard time imagining Sokka dying unceremoniously in his 70s. Main characters are supposed to have impactful, noble deaths, make sacrifices, or perform heroic deeds. However, while it would certainly be great to know what actually became of Sokka, the better death might be the quiet one. He spends much of his life fighting for a better world, and it’s good to know that he got to enjoy it in peace.

Of course, there’s the other theory that Sokka could still be the father of Suyin Beifong, Toph’s younger daughter and Lin’s half-sister. No matter how many years go by, the Toph-Sokka ship is still standing strong.