Kurogiri Satsuki

A man around 25 years old. A teacher at Reien Girls Academy. He left a strong impression on others, yet at the same time he was so very forgettable. A smile.
He resembled Kokutou Mikiya to the extent of making Azaka and Shiki perplexed. Although his countanace did not resemble Mikiya, the aura he projected was similar to that of Mikiya's.
He was a magus who was uncertain of tomorrow (the future), but hopefully clung to yesterday (the past).
Although Ouji Misaya treated him like a brother, it was unclear if they were siblings.
He was not proficient in combat, but excelled in persuading his opponents.
Satsuki possessed a very rare talent, yet precisely due to this talent, he was unable to demonstrate his powers.
Ten minutes is such a long time. ———One life time is oh so brief.

Garden of sinners Pamphlet: Kara no Kyoukai Settings Glossary