Ichiru Kiryu

Ichiru Kiryu (錐生 壱縷, Kiryū Ichiru) is Zero's younger twin brother. When they were younger, they were both taught by Toga Yagari to become vampire hunters. Ichiru, however did not seem to have the same talent as Zero's natural ability, and was often ill. Zero and Ichiru were very close as children, although later Ichiru claims to have hated Zero after overhearing that his parents preferred Zero over himself (Only because he didn't have the same talent as him).

Character concept
Name
 * Ichi is the old-fashioned way of writing "one," and ru means "thread."

Appearance
Ichiru has silver hair identical to his brother Zero, except slightly longer. He has pale lavender coloured eyes in the anime and pale grey coloured eyes in the manga. Again like his brother, he is seemingly very tall and slim in build. In the first season of the anime, he wears his hair down but in the second, he wears his hair in a small ponytail held back with a little pink string with a bell attached to it, which is a belonging of Shizuka Hio given to him by her.

Background
Ichiru is one of the twins born into the Kiryu hunter family. Due to the Hunter's curse, most if not all of his hunter powers were absorbed by his brother, Zero, which subsequently gave the latter increased power. His parents are highly skilled Vampire Hunters.

Plot Summary
Shizuka Hio let Ichiru drink her blood to strengthen him and cure his chronic ill health, although she did not turn him into a vampire and he remains a human. He now attends Cross Academy as a Day Class student by the orders of Shiki's father, Rido Kuran (and by Zero's permission). It appears Rido has promised Ichiru that he will kill those who killed Shizuka, which is probably the main reason why Ichiru is working for Rido Kuran.

When Zero was locked up by the Vampire Hunters Association, Ichiru visits him and appears to have shot him due to hatred. However, it is revealed that Ichiru was terribly wounded because he tried to kill Rido, the person he was truly after him because of his role in Shizuka's death. After he shot his brother, he convinces Zero to drink his blood so they could finally become one as they were originally supposed to be. Ichiru stated that he was happy that he wasn't dead in Zero's heart. When they hugged, he says that he feels comfortable to be in his arms, recalling a time when the brothers slept in the same bed often and were loved equally by their mother. After Ichiru's death, Zero appeared to grow vines, most likely from all of Shizuka Hio's blood that Ichiru has ingested to prevent his illness. Zero buries him alongside their parents grave.

Ichiru appears to have romantic feelings for Shizuka Hio, even though she was the one that had massacred his family and turned Zero into a vampire. In a bonus chapter, while standing over Rido's coffin, he said, "Shizuka-sama was beautiful even when she fell"... He'd always begged her to turn him into a vampire but she always refused. Shizuka did not feel the same way, perhaps only because she was too heartbroken over her dead lover, but it can be seen that she deeply cared for him.

Zero Kiryu
Ichiru's older twin brother whom he shared a close relationship.

Shizuka Hio
The person he betrayed his parents and Zero for. She told him that if he lets her take revenge on his parents for her lover she will make his body become stronger. He agreed but it is later found out that he asked her to keep Zero alive. Ichiru served her as her butler and at some point it is pointed out that he loved her.

Maria Kurenai
It is to be pointed out, but not said directly, that Maria has affections for Ichiru.

Powers
Though Ichiru was born to an elite vampire hunter, Ichiru was a sickly child who was not strong enough to become a vampire hunter and possessed no talents.