Aichi has a strong sense of what he stands for and for himself, and because of this, wouldn't do what he wouldn't do, especially in his place as Yggdrasil. He is very protective, not in a personal way, and tends to be disconnected with people, causing him to have social anxiety at times. It is rumored that he has tried to become more than just the Superior's protector and remove the Jester from the picture, but this has proven to be mostly false. While Aichi has a soft spot for Sachiro Harime, he denies often, to keep his performance in peak, tip top shape.
History:
Not much is known about Aichi, beyond his erratic behavior following the end of the Forever War, when a terrorist group known as Predominance wanted to establish their own governing rule by killing off the Superior. Each attempt was single-handedly stopped by the later to be Platinum Knight, who was recognized as Yggdrasil, and began to serve under Sachiro Harime. During the beginning of his career, Aichi worked close with Asgard and Midgard to eradicate any sort of danger which could befall their leader. The next few decades were dedicated to the security of the Superior, and the proper supervision of the 4 divisions.
Tome:
Name: Tentai Henkō - or stagnant change
Color: Periwinkle
Shape: Hourglass
Ability: The Tentai Henkō is able to collect shards of crystallized ice from the atmosphere and merge it into whatever Aichi pleases - be it a sword or a wall, though it can be draining on people around him, as it uses up an excessive amount of oxygen for breathing.