usually in mangago (for some reasons) chapters are being marked as "ending chapter" even thought that manga is ongoing. I can only guess it's because nobody knows when the next chapter is going to be uploaded.
Maybe it's because of Mentaiko's words at the end of the chapter 4, and it'as actually been a long time since it has been released so maybe that's the reason.
Anyway, I hope we get to know what's next soon (I'm dyiiiing to know what's next !!!)
I'm confused why it's marked as completed. It shouldn't be... and it doesn't seem like it's completed.