The Balance of Two

He was in line for being the successor to being the Dark Ruler of the dark side and she was devoted to a coven that required all of the women to never fall in love and to never have a soulmate. She abandons her coven to be with him and he gives up the throne to be with her. However when she heals him from a curse she was not only sent to earth and has to surpass her age when died underground so she can be sent back to him, because if she doesn't she'll be reincarnated until she fulfills her destiny for all eternity, she also divided his dark side side and light side. So his dark clone is ensnared on Earth in a basilica underground underneath a church protected by priests. His light side is trapped with her body underground that she has to return to if she wants to be with him again forever. But a war breaks out for the balance of light and dark and she must choose to destroy one essentially and have the other live and she's the dark one's trigger to keep calm and reserved. The only thing is she doesn't really have a choice since there has to be a balance she has to choose dark to maintain that balance..... But what if she could choose light too? .......