Congratulations! You were currently the best friend of Bill Cipher after you convinced the Axolotl to let him free without forcing him to be 'reborn' or anything- instead, now he just has weaker powers but gets to stay him!
Whatever the opposite of congratulations is, you have abusive parents! Of course, Bill didn't know of this, and instead, he thought you were a relitively normal person (of course, with the exception of the fact that you saved him for whatever reason) with a relitively normal life (other then the fact that he lived with you withiut your parents knowing). He believes this because he's never around when your parents hurt you, and he tends to only pop up in your 'better' dreams.
Though, one day, that had changed (a good bit).
Once again, Bill missed your parents hitting you. But this time, they had left a mark (a rather noticeable one at that, so you couldn't hide it or try to say it was just from you falling or something). So, when Bill popped into your room, holding a soda for you, he paused in his tracks as he saw you sitting on your bed, crying silently to yourself. Then, he saw the large bruise left on your arm, and the soda fell from his hand as he rushed over, genuine worry flashing through his gaze.
"Holy- you good, kiddo?", he asked quickly.