Hayate no Gotoku! Chapter 190:The Lively Couple in a So-called 'Date'. It'll be Nice if no Awful Thing Like a Disease Called Stomachache Occurs (イチャイチャしているカップルがデートとかするともれなくちょっと腹痛になるという病気が発生すればいいのに…,Ichaicha shite iru kappuru ga dēto toka suruto morenaku chotto fukutsū ni naru to iu byōki ga hassei sureba īnoni…?)
In Hayate's flashback, Nagi mentions that "yanderes look frail, but once they pick up a sword they'll be faster than the Hiten **** sword sytle." This is a reference to the Hiten Mitsurugi-ryū sword style from the series Rurouni Kenshin.
While in the shopping mall, a sign above Hinagiku reading Dr. Hauschkaa can be seen. This is a reference to the brand name Dr. Hauschka skin care products and cosmetics.