The legend of Korra: the dark apprentice

Galen the first born son of pema and tenzin was Put on a high pedestal when he was the first grandson of avatar aang and to continue the tradition Of being an air bender and when he turned 5 he prepared to be an older brother after His sister jinora was born and then bad news Struck him when he wasn't able to air bend Which made his father not noticing him for the next 3 years of his life and when he heard that he wasn't even meant to be born it broke Galen's heart and he decided that he would run away and before he left he wrote a letter to his younger Sister saying that he would always be there For her when she needed him.

This will be taken place during the entire story of legend of korra and the video game as well and it's a korra x male oc