Albireo Imma

Is one of Nagi's former companions. He entered the fighting tournament during the Mahora school festival under the assumed name "Ku:Nel Sanders" and went largely unnoticed until he approached Asuna and was recognized by Evangeline.

Story
He appears to have information on not only Nagi's whereabouts, but also on Asuna's forgotten past. Albireo appears to be a perverted fellow, as his taste in making Evangeline wear costumes made apparent in recent chapters. He's also a cunning and shrewd man with a trickster personality akin to Nagi Springfield (though perhaps a little more subtle), and is considered as one of the two natural enemies which Evangeline has (he takes great delight in verbally tormenting her), with the other being Nagi himself. Following the school festival he gives Negi confirmation that Nagi is still alive and advises that he should journey to the magical world if he is to get any closer to finding what happened to his father. He has also revealed details of Asuna's forgotten past to Eva. He also took part in the final battle facing against the revived members of Cosmo Entelecheia.

Albireo Imma has a strong affinity towards gravity elemental magic. As member of Ala Rubra, his position on the team was that of the magic healer. An interesting fact revealed in the latest chapters is that Albireo has his very own Pactio card, which means that he, in addition of being a powerful mage, is also a Minister Magi. His artifact is a series of books, with an accompanying bookmark, that can be used to transform into a specific person, using all their skills and abilities. His present Pactio is with Nagi, but he has had at least ten contracts with other mages in the past, all of whom are dead.

This perverted but handsome fellow is registered as a librarian in the Mahora Library Island. For some reason he has been "stuck" there for 10 years, and can only send out a replica of himself every year during the school festival with the help of the World Tree's magic. With some help from Yue and Nodoka, Negi was able to find the location where Albireo resides some time after the Kyoto field trip. However, it wasn't until after the Mahora Festival that Negi and his students were finally able to enter his residence in Library Island. In tune with his library theme is his Magic Password, "Papyrus Tarpis Ron Jinkou", and he refers to himself as an extremely ancient book.

He also seems to have great knowledge of the mysteries and secrets of Mundus Magicus. He is hinted to be the one who uncovered the true goal of Cosmo Entelecheia. He also seems to have known who the Life Maker really was at first glance.

Abilities

 * Pactio: Bibliothecarius Ironicus: His item is known as To Fyuron To Biographiconis. It is a bookmark accompanied by a spiraling archive of books, assumedly containing one book for every person Albireo has ever encountered in his life. Using the bookmark, he places it inside a book (with the name of the person he chooses to imitate on the cover) and draws it out in order to transform into a clone of that person, also obtaining the ability to use their powers. The artifact lacks its usefulness for Albireo as he can only keep his transformed appearance for a few minutes, if the being he wishes to emulate is stronger than him. Add to that the fact that most people are weaker than Albireo himself, he does not need to turn himself into them. Another ability of Albireo's artifact is that it can, for a full 10 minutes, allow him to transform into that person and emulate them perfectly (in thought processes, memories, emotion, personality, etc.), but the price to pay for this ability is quite high. The book that has the records of the then-copied being would lose all of its power after that time ran out, and would turn into nothing more than a simple biography (and as he says himself, "a rather mundane read"). Furthermore, Albireo will only have the memories of that person up to the point in which the biography was written (when he last saw that person). The Nagi Springfield Albireo emulated during the festival only knew of Negi as an infant, had no memory of saving and meeting Negi six years prior, and in fact assumed that "he", the real Nagi, was already dead.
 * Albireo has in his possession more than one copy of his own pactio card, showing that Albireo has been a Minister Magi and performed contracts with multiple mages, although whether they were simultaneous contracts cannot be confirmed as only one copy is shown to be active.
 * Much like the girls in the class, who have their seat numbers on their pactio cards, Albireo happens to have a Roman numeral MI (for 1,001) in the upper left and lower right corners of his pactio card. He has confirmed that this Pactio is with Nagi Springfield, the Thousand Master. Since it is currently active, the contract also proves that Negi's father is still alive.
 * Uncommon to most partners thus far, Albireo possesses two tonus (colors) associated with his card (cyaneum, [indigo] and aurum, [gold]), instead of the usual one. The reasoning for this has yet to be confirmed. It should also be noted that the gold makes his pactio a valuable and rare one.
 * this most likely is a reference to his namesake, the binary star Albireo which is made up of one yellow star and one blue star.
 * Master Magical Ability: Albireo has shown himself to be a master of gravity and healing magic.

List of spells

 * Small Heavy Black Hole (小さく黒く重い洞, Chīsaku Omoku Kuroi Hokora): Albireo Imma created a small sphere which is the equal of a Black Hole. This spell even damaged Dynamis despite his shields to a high degree. Very powerful spell.

ANIME FINAL
Alberio make a cameo appearance when the Mars are gone to crash into the Earth in the movie.

UQ Holder!
As discriped by Nagumo towards Karin while explaining Toutas Magic Magia Erebea, seems that Albireo was, at least for a short time, a member when not even a founding member of UQ Holder or has at least confederated with them for a while.

He is also the creator of the Gravity Blade used by Touta.

He is later shown siding with Negi, who is under the influence of the Mage of the Beginning. During the confrontation with UQ Holder, Albireo takes Touta into a vision of the past to show him 'everything'.

Trivia

 * Ku:Nel Sanders is the official romanization of the alias from Ken Akamatsu as seen in the Japanese version of Negima!, specifically volumes 12 (last chapter) and 13 (first chapter). It was translated by Del Rey as Ku:nel Sanders; "Ku:nel" being the name of a Japanese magazine. The Kanji for "Kuneru" also can be read to say "Eat, Sleep", a reference to Alberio's laid-back attitude, and the rather simple life he's been leading lately. And of course, the name is also derived from Colonel Sanders, which it was originally translated to by English-speaking fans. In chapter 163 of the manga, Alberio insists on being addressed as "Colonel Sanders" and an image of the founder of Kentucky Fried Chicken (with eyes censored out) is shown to bring home the point.
 * Albireo possesses a Pactio contract with Nagi Springfield, making it a possibility that they have kissed. However, as mentioned by Chamo, there are other (as of yet unknown) ways to forge a Pactio. Regardless it is one of the few same-gender partnerships known in the series (as seen by the Konoka-Setsuna Pactio in 253).
 * The fifth brightest star of the constellation Cygnus (Swan) is named Albireo.
 * Albireo is claimed to be the oldest character in the series, and has apparently been alive longer then the Lifemaker and the Magic World. How he actually knows this and how this is even possible has not been revealed.