Kohaku Celestine

'''SPOILERS AHEAD! READ AT YOUR OWN RISK!'''

Kohaku Celestine is Mikage Celestine's younger brother and the youngest son of Karein Celestine.

Etymology
'Kohaku' means 'amber' in Japanese. 'Celestine' is a name of English and French origins that means 'heavenly'.

Physical appearance
Being a member of the Celestine family, Kohaku bears a resemblance to Mikage, and, like Mikage, has blonde hair. His facial features also somewhat resemble Mikage's. Kohaku does not appear to have reached his teenage years yet, and is of average height, with a slender build.

Clothing
Kohaku was seen wearing a formal black suit, a black tie, and a white undershirt.

Personality
At first, Kohaku seems to have a cold, rude and blunt personality, speaking unkindly to Teito despite never having met him before. After being rescued by Teito, he is shown to actually be kind, as well as willing to admit his mistakes.

Rinka Celestine
Kohaku is protective of his younger sister Rinka, and rushed to her aid when he heard her being attacked by Buran.

Kokuyou Celestine
Kokuyou got angry at Kohaku for being rude to Teito, but they otherwise appear to have a good relationship.

Mikage Celestine
Kohaku clearly loves Mikage and, like his other siblings and father, is shown to mourn Mikage's passing.

Parents
He appears to have a fairly good relationship with his father. Nothing is known about his mother and his relationship with her.

Teito Klein
They did not get along well at first, but Kohaku eventually warmed up to Teito and Teito was determined to protect both him and Rinka. Kohaku has voiced his support of a romantic relationship between Rinka and Teito.

History
Kohaku is Karein Celestine's third son and the second-youngest of the Celestine children.

Manga synopsis
He is not polite to Teito when he first sees him, saying that his brother's funeral had ended long ago and if Teito is really his brother's friend, he should have come earlier. However, after Teito saves him and Rinka from an attack by the Warsfeil jewel designer, Buran, he warms up to Teito and apologises to him for having been rude earlier.

Later, it turns out that Kohaku blamed himself for Mikage's death, believing that if he had not injured Mikage during a sparring match, Mikage would not have had to join the military (Mikage sustained a scar during the match and consequently could not become a steward in the Celestine family's tradition as he was supposed to, because appearance is apparently a rather important factor in becoming a steward).

Kohaku seems to think that Rinka has a crush on Teito, and has voiced his support of a romantic relationship between Teito and Rinka. He and Kokuyou agreed that if Teito and Rinka married, Teito would then really become part of the Celestine family. After Teito was knocked unconscious and taken back to the military by Ayanami, Kohaku and Rinka were shown frantically searching for Teito, wondering where he had gone. It is not shown what happened to Kohaku after that, but it is possible that the military informed him and the rest of the Celestine Family of Teito's condition and whereabouts.

Trivia

 * It appears that Kohaku doesn't have to work, as Kokuyou said to him "not everyone is a man of leisure like you". (manga chapter 75)