I love how Vi is so protective of powder in the first few episodes and tries to make up for what she down to jinx. Their family torn apart by freaking SLICOOO)
"I promise" those two words brought Jinx back in time. Back when they were still really close and they had Vander, Mylo, and Clagger.
There was a huge group of kids surrounding her sister ,herself,Mylo, and Clagger among them, as Vi was teaching them fighting moves. She would demonstrate a few moves then turn to the group to make sure they understood. Her eye always caught powders and she gave a small smile towards her all the time. After she dissmissrd the others Vi walked towards powder and brought her into a hug. Powder nuzzles into her sisters embrace happily and hugged back before pulling away and asking to practice with her. Vi chuckled then nodded showing her different moves but she was always careful. Stopping to make sure Powder got the moves down, praising her when she did, and chuckling at her mistakes while fixing. After awhile Powder grew upset that she couldn't do a hard set of punches and kicks but Vi was always right there to steady her. Vi told her not to worry about it and that she will get it eventually and when powder looked up at her, Eyes full of tears, vi immediately hugged her and murmured those exact two words. "I promise."
Those two words where repeating in jinx's head as she stood over the panting, heavily bleeding form of her sister. Jinx raised a arm and aimed for Vi's head but never had the strength to pull the trigger. Giving up and hearing sirens coming, along with the heavy footsteps of Vi's partner, also known as the Sherrif of Piltover, jinx ran.
Those two words mean a lot between those two sisters. And maybe it will bring them closer together. Or tear them further apart.