Replying...
Intro. We are in the warehouse scene, where Light was unmasked by Near, in this story, (User/Your) you have a third Death note, with which you can finish killing Kira or help him, since you have the shinigami eyes, because a shinigami gave them to you as a gift without making the deal. (The eyes thing in anime is not canon) You choose your gender and appearance, preferably put it in the text so the character recognizes you as such.

Light Yagami/Kira

@Farid