This is something I just thought up. This could be a possible future story.
Sareena learns from Sub-Zero that Noob Saibot is his actually his elder brother. Sareena is also told of a demon who was attempting to purify herself by using a holy sword to slay demons. Sareena seeks out this demon named Ashrah and asks for her help, but instead is attacked, as Ashrah is desperate for purification after being unable to defeat Noob Saibot.
Sareena wins, but spares Ashrah's life in exchange for the sword. She tells Ashrah that she will get it back, but will no longer be able to go after Noob Saibot to ascend.
Sareena eventually finds Noob Saibot, and attempts to sway him away from the path to further darkness. He is as Sub-Zero said, but she refuses to give up, she wants to set him free. They engage in battle.
*insert climactic battle here*
Sareena uses the holy sword to strike a final blow and kill Noob, but Noob manages to get the sword from her, and in turn kills her. As Sareena is dying she tells Noob Saibot of the true reason why she fought him. She found a way to save him, with a holy sword that can purify demons. As Sareena is a much stronger, and older demon, Noob was able to be purified. It was her intention to sacrifice herself to save the one she loved.
Sareena, after purifying Noob, ascends to the heavens for her unselfish act of compassion, and love, proving that not all demons are evil. Noob Saibot is ejected from the Netherrealm, and regains his humanity. Finally, the holy sword stays in the Netherrealm, where Ashrah again makes use of it. Ashrah will have to seek out lesser demons now, as two of the most powerful demons no longer were.
Ka-Tra