Koori Ui

Koori Ui (宇井 郡, Ui Kōri) is a Special Class Investigator. He is in charge of the 4th ward, and a former protege of Kishou Arima.

Appearance
Koori is a young man of average build, with an androgynous appearance. He wears his dark hair in a sleek chin-length bob, and wears dark-colored suits while on duty.

Personality
Koori has a somewhat easy-going personality, making casual comments or jokes even during tense moments. However, he also shows an insightful nature when expressing his unease over the outcome of the raid on the 20th Ward.

Anteiku Raid
Ui joined the battle with Yoshimura, and remained fighting until only him and Suzuya were left conscious fighting the second Owl that appeared. Ui manages to hold his own for a while before losing his quinque and being forced to use one of Houji's, which he finds heavy. The Owl however gets the better of him and knocks Ui out of the fight.

When the rest of the squads make their way to the rooftop to fight Eto Ui throws Houji's quinque to Take Hirako.

Post-20th Ward One-Eyed Owl Battle
After the Anteiku Raid, Koori is shown sitting on a bench with Hirako, discussing about the outcome of the battle and that they're not sure if they really even won the battle.

Auction
Koori was promoted to Special Class during the time skip and has become a member of S3.

He arrives at the Auction after having taken part in the defence of the Quinque Steel Transport and is seen giving orders to CCG members.

Kishou Arima
Arima is Koori's former mentor, being partnered together in the past.

Take Hirako
As both of them have had Arima as a mentor and partner, they seem to have a friendly relationship with each other and discusses about battles.

Power and Abilities
Koori is a highly-skilled Investigator, referred to as the "Hope of the Arima group". He is an exceptional fighter, able to survive for an extending time while facing the One-Eyed Owl in battle. An acrobatic daredevil like Suzuya, as implied when stealing Itsuki Marude's motorcycle together with him - though more sane.
 * Taruhi: A halberd-shaped quinque he uses in battle against the Owl.