I am not going to write this idea for a while, i have far too many stories ot work on... but someone else could use this if they want to. The Hyuuga's were too interesting and underused, they needed to be expanded on in my mind... and so I came up with an idea for a character someone could use.

A girl from the most distant branch house, no one think she can even used the Byakugan. Her parents got together as they were the farthest members of each branch and wanted to make sure their kid could use the Byakugan. They are not kind to their daughter.

Determined to be powerful, if only to gain freedom from her clan and family, she trains insanely hard. Slowly, she takes the weak taijutsu lessons she gets ( as each branch learns less than teh Main Branch) and creates her own moves.

She uses Ninjutsu too, not just taijutsu and excels as a ninja. She chooses to be more than her family, her clan.

Eventually, she does activate her eyes and shows what the Byakugan can do when used by someone that thinks out of the box. She may not be as pure as Hinata or might as well be a main brancher Neji... but she is very powerful with her eyes and training.

She might, it's just an idea, do an Itachi and kill the main branch... just a thought, i hate the slavery angle and how they even seem to endorse it in cannon.

She teaches herself as much as possible and gets into ANBU.

She is given the mark later in life, they never assumed she would get the Byakugan to activate.

She loathes most people including Neji and Hinata...

She makes the style her own, and does figure out some Main Branch Stuff like Neji but hides it out of fear. She knows he is favored enough to not be hurt...

We need to see the abuse of the mark, that is vital...