Umaru Doma is a model student who has a hidden side: when she gets home each day, she puts on her hamster hoodie and turns into a sluggish otaku fond of junk food. As Umaru continues these daily antics, the friendship between her and her classmates—Nana Ebina, Kirie Motoba, and Sylphinford Tachibana—deepens, and more and more interesting events begin to unfold. Of course, these events give rise to numerous questions. What did Nana ask of Umaru's brother Taihei? Who is the mysterious girl with the diamond hairpin? And most important of all: why does this girl seem to know Umaru? These questions and more will be answered in Himouto! Umaru-chan R!

A peculiar transfer student named Ougi Oshino has just arrived at Naoetsu Private High School. She is quickly introduced to senior student Koyomi Araragi by their mutual friend Kanbaru Suruga, in hopes of obtaining advice regarding a strange discovery she has made. After taking a look at the school's layout, Ougi notices that a classroom has appeared in an otherwise empty area—a place that should not exist. Unsure if this is the work of an apparition, Araragi and Ougi attempt to unravel the truth behind this enigma. But Araragi soon discovers, after finding himself locked in with Ougi, that the room holds the memory of an event he had long since forgotten. [Written by MAL Rewrite]

Super OVA 1: Based on a story from vol. 27 of the manga, Shampoo and Ukyo arrange to travel to a cave that is legendary for breaking up couples. They hope they will cause Ranma and Akane to break-up and Shampoo hopes to ditch Mousse the same way. Super OVA 2: "Jaaku no Oni" (lit. "The Wicked Demon") was released in 1995. Based on a story from vol. 29 of the manga, an Oni (that wears a tiger-striped diaper just like the Oni of Urusei Yatsura) escapes it`s sealed box and begins to possess people in the neighborhood. Super OVA 3: This is a story from vol. 31. Ranma disturbs a doll that takes revenge on anyone that shows it disrespect. In order to teach Ranma a lesson, the doll possesses Akane and tries on many occasions to attack him. (Source: AniDB)

Episode 0 of Dies Irae.