The Fire Nation has been portrayed to be pretty ruthless in the 100 years that it festered without the presence of the Avatar. Throughout the war, the country committed numerous atrocities and tried to set the Fire Nation as a hegemonic force on the entire planet.
A part of this process was making sure that the other bending arts were eradicated, if not heavily suppressed, so as to allow the Avatar Cycle to be restricted to the Fire Nation alone. After killing every single Air Nomad and enslaving the Earth Kingdom, the Fire Nation also murdered and enslaved a slew of Water Tribe benders, specifically from the Southern Water Tribe. An Avatar theory suggests that this could have been because of a certain The Last Airbender villain, who could be squarely blamed for these atrocities.
Hama was the reason benders went extinct in the Southern Water Tribe
It goes without saying that the Fire Nation always viewed fire as the superior element, and considered other elements to not be a threat. The only thing that they thought could stand in their way was the Avatar. However, when Hama developed bloodbending and escaped her Fire Nation guards, the Fire Nation was sure it had to start executing waterbenders rather than simply capturing them.
Hama was one of the most dangerous waterbenders to come out of the Southern Water Tribe, one whose bloodbending, if weaponized properly, could have spelled doom for the Fire Nation. However, as waterbenders need only learn the skill and use rather than having a special talent, The Fire Nation could have begun rounding up benders to execute them to protect its own hegemony in the world theatre.
Hama could be the reason Katara’s mother is dead in Avatar: The Last Airbender
Katara’s mother was slain by the Fire Nation for being a bender, a fate that was spared to Katara because she was able to hide the fact that she is a bender. Hama’s stunt using bloodbending to escape scared the Fire Nation so much, that it can be easily assumed that she was the reason all the benders were slaughtered in the Southern Water Tribe rather than simply being captured.
While there were members of the Southern Water Tribe who were still alive and well (such as Katara and Sokka’s father), It was only through clever tactics and strategies that they survived, which might have not been possible at the beginning of the attacks, when the Tribe was worried about protecting it’s young and vulnerable from an onslaught of Fire Nation attacks.
