Shu Akitsu

Shu Akitsu (秋津秀, Akitsu Shū) is an Ayakashi Majiri and a member of the Night Troop. He is friends with Sen Kagemiya and Dai Yaegashi. Both Shu and Sen later transfer to the Intelligence Unit, and begin attending Karasumori Academy.

Appearance
He is a tall, thin boy with hair that stands straight up on his head. His eyes always appear to be closed (except during extremely rare occasions of shock), but as he is still able to see, this is likely an exaggerated squint.

Personality
Shu is polite and friendly, which serves as a sharp contrast to Sen (who is known to interrupt Shu by shoving his face to the side). He usually takes it upon himself to apologize for Sen's rudeness. Shu gets along well with nearly everyone, especially Tokine (which at first greatly bothers Yoshimori) and Shizue Yukimura.

History
In the anime, Shu was originally on the same team as Sen, Dai, and Gen Shishio. Gen's solitary nature caused several problems for the team, especially during a mission to destroy the Ayakashi Tanimatagi. Gen's decision to attack head-on endangered the rest of the team, and they abandoned the mission to complain to Miki Hatori, demanding that Gen be removed from their team. However, Hatori's main concern was that they had abandoned Gen.

Remembering Gen
Shu attends Gen Shishio's funeral with the rest of the Night Troop. In the anime, he confronts Sen about his skipping the funeral, prompting a flashback of a violent confrontation Gen had with another member, Shoki. Shu points out that it was entirely Shoki's fault, and recognizes that despite Sen's complaints about Gen, he actually considered Gen a friend and admired his strength.

Meeting Yoshimori
The Night Troop is transferred to Karasumori to prepare for Kokuboro's next invasion, and Sen, Shu, and Dai all observe Yoshimori at various places before confronting him. Sen challenges him to a game, pitting the three of them again Yoshimori, and starting before Yoshimori has a chance to answer. Yoshimori captures Dai, and nearly catches Shu, but is startled when Shu uses his wings to fly out of range, allowing Sen to slip behind Yoshimori and threaten to cut his throat. Yoshimori then activates a very thin Zekkai armor, destroying Sen's claws and freeing himself. All three are shocked by Yoshimori's great power (which he showed little evidence of before). Yoshimori promises them that he will take revenge on the one who killed Gen.

The Box Plot
Shu is one of several Night Troop members that helps locate the many boxes planted at Night Troop Headquarters by the Elder Kakushino.

Intelligence Unit
As Yoshimori begins his third year of middle school, he is shocked to learn that Shu is now a first-year high school student at Karasumori Academy. Shu explains that he and Sen (who is in Yoshimori's class, but skipped the first day), now part of the Night Troop's Intelligence Unit, have been assigned to investigate Karasumori. He mentions that they are not there to assist the kekkaishi as Gen was, and like Sen, observes Yoshimori and Tokine while they are unaware. Despite this, when Saki's butterfly Ayakashi began to appear around the school one day, Shu destroys several without being asked. He agrees to continue helping at Tokine's request, eventually destroying a hundred butterflies. The butterflies continue to increase in overwhelming numbers despite how many are destroyed, and they are also gradually getting stronger. Shu calls Sen to warn him that some students can now see or hear the butterflies, while others are feeling sick or fainting. Shu continues destroying the butterflies, but realizes his efforts won't be enough. Sen calls him outside and explains that the four Kekkaishi (Yoshimori, Tokine, Shigemori, and Tokiko) will attempt a Four-Corner Formation Kekkai around the school, with each of them stationed at a corner, and slowly move only the Ayakashi away from the school. Shu is surprised that the rival clans would work together so easily, and takes to the air with Sen on his back to observe. The Kekkaishi eventually contain and destroy all the butterflies.

Powers & Abilities
Enhanced Agility/Strength: Shu's body is more powerful than the average human's: he is able to launch kicks with great speed, and can land after falling from a considerable height with no sign of injury.

Ayakashi Transformation: Vampire: Shu is an Ayakashi Majiri, able to transform into a vampire. There is little indication of this normally, but his full transformation can be triggered by outside means. In this state, Shu becomes a ferocious berserker, unable to distinguish between friend and foe. In addition, his primary instinct is to attack people, especially young girls (and among them, especially virgins), and suck their blood. He also flies at twice his usual speed while transformed, and his hands and feet become claw-like. However, Shu's personality makes him largely unsuited for battle, so he normally only uses partial transformations, and even those are primarily for non-combat purposes.
 * Wings: Shu can instantly sprout a large pair of wings from his back to escape danger. He sometimes carries a comrade on his back, though this can be troublesome, depending on their weight and the flight time.
 * Devil Ear: By enlarging his ear, Shu can enhance his hearing. This is useful for picking up far-off voices.

Sen Kagemiya
Shu and Sen are close friends, to the point where Shu remains a member of the Night Troop's Combat Unit for an extended period, solely because Sen does the same (even though they both are admittedly ill-suited for combat). At first glance, they do not appear to get along well: Shu is kind and makes friends wherever he goes, while Sen typically goes out of his way to annoy even his friends. Despite this, Shu knows Sen very well and can usually guess how he is feeling, especially when Sen is reluctant to admit his own feelings.

Trivia

 * Shu explains to Tokine that it's fairly normal for Night Troop members to be in multiple units at once. As an example, he states that in addition to having just transferred from the Combat Unit to the Intelligence Unit, he is also still part of the Cooking & Provision Procurement Units.
 * Shu's canines are pointed, hinting at his Ayakashi Vampire.