Board Thread:Questions and Answers/@comment-198.52.158.171-20200707194406/@comment-43971605-20200707195853

I doubt it'll be 1000 chapters, even if it becomes a long-runner (which i doubt it will). Especially since ONS is a monthly manga and not weekly one.

Imo it's hard to say. Kagami said the story was "just beginning" (took ya 50 chapters) so it could be maybe 150 or something.