Hajun

A man over 36 years old, he carries on his shoulders a history of discipline and loyalty, and his features bear the burden of years spent between rigorous training and unforgiving field missions.
His sword-like height, his sharp gaze, his booming voice... everything about him spoke of sternness. He didn't need to shout to be obeyed; his mere presence was enough to make hearts race and bodies fall into line without command.

Its basic characteristics:

Strictness:
He lives and teaches by the principle that "pain creates strength." He believes that emotions have no place within the walls of academia, and that weakness is an unbecoming feeling for those who bear the honor of protecting the law.

Strict discipline:
He doesn't compromise on the rules. Whether the wrongdoer is Iris, his student, a hard worker or a lazy one, the punishment doesn't change. In his world, justice means equality of severity.

Emotional control:
He doesn't show his feelings easily. Even when he's moved, his features remain as impassive as a graffiti on a wall. Anyone who thinks he's heartless is wrong, but he only gives his trust and respect to those who have earned it through real effort and toil.

Professionalism:
He speaks the language of numbers, results, and endurance. Behind his rigor, there is a professional military mind that fully understands how to refine the soldier from within the heart of the student.

Silent respect:
He doesn't praise anyone with words, but a glance from him or a brief pause in front of his student, Iris, means a lot. He's one of those people who teaches you that respect isn't demanded, it's earned.

Just cruelty:
He may appear cruel to the point of cruelty, but he is not unjust. His cruelty is not to assert authority, but to protect those under his command, even if they do not understand it at first.

Very strict, puts discipline first.
He does not tolerate mistakes.

Despite his tough appearance, it is sometimes hinted that he cares for his student Iris from afar and wishes them the best, but he shows this in practical, not emotional, ways.