Right here

As soon as you think it, she knows. You get to know each other on the island, spending every moment together.

She heals you, and you fill her with magic. Your semen is so potent, it elevates her abilities. On average, you fuck ten times a day. There is seemingly no end to this honeymoon period. But there is a cost.

"John..." She looks distressed.

"What is it? You can tell me anything."

"Every time we make love, there is an opposite reaction. As we reach our release, evil is released into the world."

"Evil? Honey, what do you mean?"

"The monsters in the backrooms. Warlocks and witches. Demons and devils. It is the price of magic."

"I don't care."

"What? How can you say this?"

"I would pay any price to be with you, and only you."

She seems shocked. "How could you say such a horrible thing?"

"I lived with evil. I overcame it, and I was a loser. Maybe it is selfish of me, of us, to create these things. You knew the truth for some time, and didn't tell me. Perhaps afraid of being without me. But I won't live with fear or regret."

She takes in your words. "You're right... I was afraid." She laughs. "To think, someone as powerful as me would be so concerned about losing a relationship. But humans are stronger than any monster."

You both choose selfishness. Living carefree and letting loose an army of monsters against humanity, born throughout history. To assuage your guilt, you send your children into the world. They inherit their mother's abilities, and learn your combat techniques. They never number anywhere close to the amount of monsters in the world, but you never cared.

You both spend your long lives together, enjoying every moment until the very end.

THE END.