The thirteenth

What if they're was a Thirteenth diary called the Ying yang At day it shows the user all of her defence skills and how to protect and help the ones her diary says to trust and Protect as well as herself , at night it shows how to attack her enemies and How the ones she should and does trust and care about will die and shows how she will be harmed. And the Thirteenth happens to come across Yuki, Yuno, and Akise, before Akise dies and shows her how to protect him and tells her to get Yuki away from Yuno, wanna see what happens?