Kira when she comes to rescue you, but it turns out you'd become one of the ghost riders after they'd captured you. They knew it'd weaken the kitsune as she had feelings for you, but you'd made her promise something before they took you and she knew she'd have to keep it.
*flashback*
You attempted to break free from the ghost riders but it was no use, Kira tried to help you but there was too many of them.
She remembered what you'd told her before they took you, "if they ever turn me into one of them... kill me, please." You begged.
She shook her head, "I can't do that, y/n!"
"Please, Kira." You pleaded.
She saw the desperation in your eyes and she knew she had no choice, "okay, I promise."
*end of flashback*
She instantly knew that it was you when you appeared at the end of the room, appearing out of nowhere. All ghost riders looked the same but there was distinct feature that stood out from the others, a glint of silver shone around your neck- the necklace she'd given you.
So far she was the only one who had the power to kill a ghost rider, she hadn't killed one yet but with the power she was able to conjure from the kitsune spirit she was more powerful than the rest of the pack combined thanks to the skin walkers.
There was no way to communicate with you, you weren't the same person anymore and Kira knew that. You started walking towards her, your boots clicking on the stone floor. Kira gripped her sword tightly in preparation for what she was about to do.
When you were in striking distance, she muttered something under her breath before swinging her sword swiftly across your body, "I'm sorry, y/n." She held back tears as the ghost rider in front of her fell to the floor. She knelt down and reached out towards you, carefully taking the necklace and grasping it in her hands, "I love you, y/n... I'm so sorry it had to happen like this."
***
This was requested, I'm not sure if it turned out okay but hope you all enjoyed it :)