Yuno Gasai lives a normal life as a first-year in high school. She gets along well with her parents and even has a small circle of friends. However, she cannot help but feel as if someone is missing from her life, someone so important to her that it was as if she had lived another life trying desperately to stay with them. 
 
After a class trip to the beach, Yuno returns home; but in the middle of the night, she receives strange messages from a voice only she can hear. The voice informs her of the person she is desperate to meet and that she must find him. Soon, she finds herself in a mysterious realm, her only goal being reunited with the person she cannot remember. Though obstacles stand in her way, Yuno will stop at nothing to meet her beloved once again. 
 
(Source: MAL Rewrite)

This psychological thriller, based on the manga written and illustrated by Sakae Esuno, is about Yuki, a loner who's not very good with people. He prefers to write a diary on his cell phone and talk to his imaginary friend, Deus Ex Machina &ndash; The God of Time and Space. However, Yuki soon learns that Deus is more than a figment of his imagination when he makes Yuki participate in a battle royale with eleven others. The contestants are given special diaries that can predict the future, each diary possessing unique features that give it both advantages and disadvantages. Within the next 90 days, the contestants must try to survive until there is only one left standing. The winner will become the new God of Time and Space. 
(Source: FUNimation)

12 Diary Holders