Azusu and Kiachu grew up together; they learned almost everything they know together, so it's no surprise they would have very similar life philosophies and ways of doing things.
At first glance, Kiachu is clearly more cheerful, while Azusu is gloomier, almost brooding.
So it's surprising when people find out that the most unmerciful one is Kiachu, perhaps because while Azusu had at least a mother, Kiachu was completely on his own.
Kiachu is not prone to violence, different from Azusu that gets riled up relatively easily, but when he is pushed too much he will not stop until he feels the person who angered him got what they deserve, he doesn't forgive grudges, and is more bitter than he may look like









