IOSYS is a prolific doujinshi circle that specializes in music remixes, particularly vocal remixes of the background music from the Touhou series, with 33 albums (as well as several karaoke/alternate-remix and best-of albums and two re-releases) just dealing with Touhou in the past six years. Many of their vocal remixes have been given music videos by various artists.IOSYS's (Touhou) albums to date:
Alternate Character Interpretationinvoked: IOSYS, being deeply ingrained in Touhou fandom, tends to take many of the same liberties with characterization as the print side. In particular, they are virtually the Trope Codifier for the "Tsundere Alice" characterization, thanks to remixes such as "Marisa Stole the Precious Thing", "Alice —> Sweet", and "Doll's Play".
Audio Adaptation: Touhou Hyousetsu Kashuu, Touhou Bubbling Underground, and Touhou Chotto Matten each contain three or four drama tracks that either tell a continuing story (in the case of Touhou Hyousetsu Kashuu) or shorter, independent ones.
Clumsy Copyright Censorship: Averted, for the most part. IOSYS re-released its Touhou Tsukitourou album from 2006 as Touhou Tsukitourou Safe! in 2009. The album had three new tracks, drawn from other IOSYS sources (including a previously limited-issue track), while removing three others. The three removed? Parodies of songs from Saint Seiya, Japanese singer Yousui Inoue, and Haruhi Suzumiya (the below-mentioned "Kire Kire Mayoi"). The album doesn't suffer from the removal.
Concept Album: Touhou Bubbling Underground revolves around Marisa and Nitori club-hopping in the underground hell.
Also of note is "Reason to Fly", for having only the first two words being comprehensible.
"Marisa Stole the Precious Thing" deserves mention for having gratuitous English, Chinese, and German all in the first verse!
Intercourse with You: "Border of Extacy" and "Ecstasy Masochistic" take this to over-the-top levels.
Covert Pervert: "Border of Extacy" is Youmu's imagination running wild with what Yuyuko does with Yukari.
Kanji Salad Album Title: The kanji for Chotto Matten, Unfufuufu, Souyuu Shimpi were randomly chosen for their pronunciation, and make absolutely no literal sense whatsoever. To date, only one of these titles, Souyuu Shimpi has had a literal translation done to show how non-sensical they are (Eastern Thoughtfully Deep Forest Chicks).
Long Title: Several, which only get longer when the songs are themselves remixed, but the prize goes to the Nico Nico Dougaparody "[Singing Attempt] The Brides that Queue Up the Affected Area are Impending the Precious Sun, Perfect Ignorant Fools! [Prismriver]", a medley of several of IOSYS's most popular songs, as performed by the Prismriver sisters.