What to fill this space with... uh, I'll talk about chapter length! This chapter is quite short, 30+ pages, chapter 4 is about 45 pages long... and... chapter 5... is 120 pages long, I mean, what in the nine hells... Thankfully, chapter 6 will be just 16 pages long.
That's it, chapter link here.
Edit: Only Sense Online Volume 5 release date has appeared! Yes, justice! 20th of May!
Edit2: By the by, apparently Only Sense Online Manga's Volume 1 is coming out on the same day! While I'm still not satisfied by the art, I pray for its success! (That aside, the manga tries to follow novel closely, minus detailed explanations as a matter of course.)