The original web series basically have two mode
The episodic comedy with different cases and the more serious plotline arc. So yea it might feel sudden
What the hell they have been feeding the kids during their elementary school years. Seems like they either grow up to be complete freak, pervert, riddled with depression and sometimes all three.
So a little fun fact about this chapter, Masa ability does let him absorb knowledge and in fact in the first video of the YouTube series it is actually the very first ability his Black Hole shown.
Because there seems to be a difference I think it's not a spoiler but in the web series Masa is actually instantly smitten at the first sight upon seeing gend bend Hikaru(Hikari) and absolutely crushing on Hikari the entire time
So, not so fun fact in pg. 12 Halloween night. Masa recommend Hikaru to be some sort of lantern but really early in web series and early in their relationship Masa managed to upset Hikaru by calling him "Lantern" Multiple times to the point Hikaru ignore him
In regards to Taira Hitoshi
The tl section were right, he should have been introduced much much much later in the series considering he is only introduced recently
The webvideo series is entertaining enough as is and even though there is no subtitles I highly recommend people to watch it as the...
You should try to watch the videos. It used simple enough dialogue that even my limited Japanese could understand it, and even if there're words you didn't understand often times you could pick it out from the context.