<p>When discussing Book 3 of TLOK with my 9 year old cousin, he came up with an very bizzare theory that I simply could not poke at. I still think about it but something doesnt seem right
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</p><p>-Su is actually Yin's daughter. She was disowned by Yin for hating the Earth Queen. As shown in "The Earth Queen" Yin scolds Tu for insulting the Earth Queen. In the Metal Clan, Su says the Earth Queen is horrible. It is evident Yin's children were Earth benders as Chow and San granted Bolin and Tu Earth bending. Su may have gotton it from Yin as well
</p><p>-It is common for families to make their childs middle name their parents name. Thus Su's full name:
Su-
Yin-Beifong (infact me and my cousins middle names are the same as our fathers)
</p><p>-Toph had one daughter: Lin. When Toph realized Lin wouldnt follow her own path, she tried to adopt an Earth bender from the Earth Kingdom. This is how she obtained Su who was disowned by her mother Yin. Toph never revealed their fathers to hide the fact Su is adopted
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-When Su is first introduced and called "Suyin Beifong" she says "please call me Su". She doesnt want "Yin" to be part of her
</p><p>-Toph got Lin to believe Su was her
half-sister as reasoning Su did not resemble Lin much. If you look at their hair textures. Lin and Toph have
Straight hair curving behind their head, while Su and Yin's are curvy throughout. As Su was disowned then adopted, she wasnt very nice during her childhood (as shown in Old Wound flashbacks). Su in these flashbacks also never referred to Lin and Toph as sister and Mother. She didnt see them as family
</p><p>-Upon Su's banishment and realized she was just looking for family, she starts refering to Lin as her "sister" as her view on family is different. Anyone she cares for is family, not just biological. She even referred Aiwei as family despite not biologically connected before he was deemed a traitor
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</p><p>I didnt want to disagree, he went off to joke about how many "Bopal" ships would be sunk as this would make Opal Bolin's cousin, despite this wouldnt make them like eachother more or less. I joked back that Tu and Opal would have an Earth vs Air bending brawl over who's Bolin's best cousin
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</p><p>What do you think?
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