The information was revealed through the author's comments in volume 23 . Volume 24 is scheduled for July 17th.
The author also revealed that this will be his last work , check out the author's comment below:
“The story is in its final phase for both the manga and for me, I intend for this to be my last manga, so please follow me until the end”
Atsushi Ohkubo is also the author of the renowned “ Soul Eater ”, and released “ Fire Force ” on Kodansha Comics in September 2015 .
Source: ANN
