Kasen disappeared five years ago searching for Pi-chan, so it's possible she's been around Nitori for six years. Or at least 6 most annoying youkai awards (which could be done in a little over five if Yamame landed shortly before the first one).
Nitori-san!Is it because I'm in another dimension...?I can't control time...?Oh!Look there!...six years running...We've got a big scoop!KkrrrkHoo, boy...Ah!...and playing a game of sepak takraw!Ehhh?Not even Nitori would fall for a lie like that.Sakuyahime-sama...!No choice...I'll use my trump card!ShwipCucumbers wearing Gothic Lolita fashions are getting together...However blatantly addicted to cucumbers she may be......and despite her winning Youkai Mountain's Annoying Youkai Grand Prix...Rraaaagh!Goth-Loli cucumberrrrs!