Sebek

Sebek is a tall boy with fair skin. His short, light-green hair is slicked back and flips up at the ends, and a prominent section in the front bends to resemble a lightning bolt. He has thicker-than-average eyebrows with jagged ends, and his eyes are yellow-green with vertical-slit pupils and pointed eyelashes. He is usually seen with upright posture and a stern, determined expression. When his mouth is open, sharp fangs are visible. Sebek is loud, hot-blooded, and prideful. Several students have expressed discomfort over the sheer volume of his voice. Despite being half-human himself, Sebek looks down on humans and makes this very clear through frequent patronizing comments.

However, he is also an honest person, and will openly acknowledge others (human or not) for their talents or other impressive skills. He is blunt and not afraid to express his thoughts. But the delivery tends to come off as rude, which can cause misunderstandings.

Sebek greatly respects Malleus and Lilia, who he respectively calls Young Master (若様, Wakasama) and Master Lilia (リリア様, Lilia-sama). He becomes much politer and meeker when addressing them. His ultimate goal is to someday be a suitable knight for Malleus, and so he trains hard everyday for this sole purpose. Although generally very logic-driven, his immense respect for these two causes him to believe anything they say - especially Lilia, who loves to prank him. Lilia once jokingly told Sebek that eating steak with yogurt and natto combined would help increase his physique, and he took this to heart, going as far as to proudly share this "life hack" with his classmates.[1]

Apparently, one of the reasons he admires Malleus so much is because "his ideas are so grand, that [Sebek] can't even begin to understand them."