Sometimes even Katara and Sokka forget that they aren't actually siblings. They both have brown hair and share Chief Hakoda's good-natured smile, but neither of them are actually even his children. Sokka's father was a brave man (rather rash, by all accounts) and one of the first people who decided to try and stand up to the Fire Nation Army. He organized a small raiding band and burned down one of their ships encroaching Southern Water Tribe Territory in a sneak attack. Unfortunately, Sokka's father and five other men died in the skirmish after the guards on the ship were alerted to their presence. His mother had died at childbirth and so Sokka did not have any parents left.
Chief Hokada, unable to have any children, took in the young boy as his own and paid a young woman to nurse him with her own son. His wife adored Sokka too, although as the boy grew older he always clung to his father, carefully watching the older man as he hunted and interacted with his men and imitating his humor.
Katara is Chief Hakoda's niece. His brother died about a year after Sokka's father in another unsanctioned attempt to harry the Fire Nation, and her mother wasn't strong enough to continue without her husband and died of a broken heart a few months after. She's more closely related to Hakoda than Sokka, and so he is more obligated to care for her, but again, neither Hakoda nor his wife mind. It will be good for Sokka to have a younger sister.
Children are precious to the Water Tribe and embody their future. Much care is given to raise them properly. If a child misbehaves, anyone can discipline them as long as the punishment is within reason. Men teach the boys hunting and how to be strong fighters, and the women show their girls how to breed penguins, the art of gutting and cooking fish, repairing nets and sewing. The passage from childhood into adulthood is a notable event.
Katara can't remember her own mother, a woman who taught the young children how to play the bone pipe, her long slender fingers sliding up and down the hand-carved holes, the beautiful, eerie tune filling the night air beside the campfire. For Katara, her real mother died in the Fire Nation Raid when she was five or six, pressing Gran-Gran's engagement necklace into Katara's hand. And Sokka's father will always be Chief Hokada, bending down to tell his war-painted son to stay and protect the villagers and his sister instead of the burly, competitive man who played Pai Sho and did his best to always hunt the most food for their tribe.
To Katara and Sokka, they are more than just siblings and they never discuss the fact that Hokada isn't actually their father, because in many ways he's more than that. Blood relationship isn't important to them—even Aang has become a part of their makeshift family. After all, didn't Bato make him a part of the tribe when he wrote the sign for "Trust" on Aang's forehead? Family looks after each other, and Aang is now Water Tribe despite the arrows tattooed on his skin. After the war, Aang will always have a place he can come back and call home.
-
-
-
-
This isn't necessarily true. It's just an idea to think about, and something I chewed on mentally for a while before writing it down. Comments and reviews appreciated!