Future Diary: Grand Battle is a fanmade expansion to the Future Diary series.
Azami Kirisaki: The main protagonist of the new series, she enters the new single elimination survival game at the New Collsseum of Time, She is the 13th Diary User who has a little sister named Kasumi Kirisaki whom she dearly loves.
Unnamed 14th Diary User: A new friend of Azami's, He's a 17 year old From America, he uses a Genre Diary.
Unnamed Other Diary Users: her fellow opponents of the Tournament.
Unnamed 16th Diary Tournament's Masterminds: The twin-16th Diary Users and the main antagonist of the series.
Muru Muru: is the servant of Deus Ex Machina and serves as a judge along with him in his new tournament
Kasumi Kirisaki: Azami's baby sister who she loves.
Ai Mikami: Marco's wife and the tournament's preliminaries round host.
Marco Ikusaba: Ai's Husband and the tournament's round 1 host.
Akise Aru: The tournament's round 2 and round 32 host, he's Kasumi's crush.
Minene Uryu: The tournament's round 16 and the finals host.