The Melancholy of Haruhi Suzumiya

Haruhi Suzumiya is a light novel series which began with the first book, The Melancholy of Haruhi Suzumiya, in 2003. It was adapted into an anime in 2006 by Kyoto Animation. Due to Haruhi Suzumiya's popularity at the time the Lucky Star anime was first broadcast, Lucky Star has made more references to its fellow Kyoto Animation work than other anime or manga series.

Overview
Haruhi Suzumiya is the general name for a series of light novels written by Nagaru Tanigawa and illustrated by Noizi Ito, and subsequently adapted into other media. The story follows the title character, Haruhi Suzumiya, a high school girl who can unconsciously change reality, and her strange antics with her school club, the SOS Brigade, that she founded to investigate any mysterious happenings. Haruhi forcibly drafts her cynical classmate Kyon who narrates the series, and similarly recruits three additional members into her club: the silent bibliophile Yuki Nagato, the shy and timid Mikuru Asahina, and the friendly "mysterious" exchange student Itsuki Koizumi. These members soon reveal themselves to Kyon as the extraordinary characters Haruhi is seeking, being an alien, a time traveller and an esper, respectively. They are each sent by their various organizations to observe her and hold her reality warping powers in check by maintaining the illusion of a normal life.

Haruhi Suzumiya
(涼宮ハルヒ Suzumiya Haruhi)

Gender: Female

Age: 16

Voiced by: Aya Hirano (JP), Wendee Lee (EN)

There are numerous references to Haruhi herself in the Lucky Star anime. The most important reference is the casting of Haruhi's original and dub voice actresses as Konata Izumi, the main character of Lucky Star.
 * In episode 4, Konata's birthday gift to Kagami Hiiragi is Haruhi's "brigade chief" armband.
 * In episode 10, Konata's room is shown to feature a poster of Haruhi and the rest of the female cast in bunny suits.
 * In episode 12, a Haruhi cosplayer can be seen at Comiket.
 * In episode 15, two Haruhi figurines can be seen, one next to Konata's bed, and another on her bookshelf
 * In episode 16, Konata herself cosplays as Haruhi Suzumiya while working in a café alongside Yuki, Kyon and Mikuru cosplayers, and also performs the Hare Hare Yukai dance with "Mikuru" and "Yuki".
 * In episode 17, Konata reads the July 2007 issue of Comptiq, which features herself on the cover and Haruhi on the back.
 * In episode 20, Haruhi herself appears on a cola commercial which the Hiiragi twins watch at home. Haruhi is seen running towards the shore of a beach while wearing a white bikini.

Mikuru Asahina
(朝比奈みくる Asahina Mikuru)

Gender: Female

Voiced by: Yūko Gotō  (JP), Stephanie Sheh (EN)

Mikuru is a female who travelled back in time to observe Haruhi. She is an unwilling member of Haruhi's SOS Brigade, but has since become their mascot. Mikuru is referenced in Lucky Star several times.
 * In episode 10, a Mikuru figurine stands on Konata's television.
 * In episode 12, a Mikuru cosplayer can be seen at Comiket.
 * In episode 16, Patricia Martin cosplays as Mikuru Asahina while working in a café alongside Haruhi, Yuki and Kyon cosplayers. She also performs the Hare Hare Yukai dance with "Haruhi" and "Yuki".

Yuki Nagato
(長門有希 Nagato Yuki)

Gender: Female

Age: 4, (17 Physically)

Voiced by: Minori Chihara (JP) Michelle Ruff (EN)

Yuki is a bibliophile humanoid interface created by Data Integration Thought Entity, whose responsibilities involve monitoring Haruhi and the investigation of an unexplained "explosion of data" three years prior to the present story. She possesses an ability to manipulate her surrounding environment, or "data", as quoted by her. Yuki is very quiet, or like a robot, but can speak at length when it has to do with her mission or a problem that has arisen. While she always seems to be engrossed in her reading, she comments that she is only relatively interested in them. Yuki gives hints and aid to Kyon throughout the series. She almost never shows any emotions, but there are times when she shows interest in certain things, such as programming computer games and playing them, as well as reading.

In Lucky Star there are a few references to Yuki. Foremost would be a costume Konata wears during the 24th episode of the Anime and the OVA; the magician outfit she wears during the skit named Tsundere-lla is designed after that of one Yuki wears during a concert scene.

Another small reference to Yuki occurs in the 15th episode of the anime. Sōjirō Izumi comes into Konata's room to ask her if she would be okay with him remarrying. There is an intermittent silence while Sōjirō gathers up the courage to ask her. To break the tension he asks her if the book she's reading is interesting, to which she responds with the single word: "Unique." A similar exchange happens in the (chronologically) first episode of The Melancholy of Haruhi Suzumiya; where Kyon asks Nagato what's she's reading. After she picks up the book and shows him, he then asks if it is interesting, to which she responds simply with the word "Unique."

A third tie to Yuki Nagato worth mentioning is that her Japanese Seiyū, Minori Chihara, is also known as the voice of Minami Iwasaki. Both characters can also be noted as having both similar personalities, similar voices (both speaking in a monotone fashion), and bearing a reasonably similar appearance to each other. Both also bear a resemblence to Neon Genesis Evangelion character Rei Ayanami in both appearance and personality (Minami, though, is a parody of what is referred to by TV Tropes as a "Rei Ayanami Expy").

Links

 * Haruhi Wiki (Fan operated wikia)
 * Haruhi Suzumiya - Wikipedia
 * Official Kadokawa Shoten 'Haruhi Suzumiya website (In Japanese)