Felix has wavy, crimson-red hair with bangs that fall into his light gray eyes. As an imperial knight, he has a tall, lean stature with long, muscular limbs and broad shoulders. He is noted by several female characters to be very attractive. As a guard, Felix typically wears a double-breasted shirt, matching pants, boots, and a black cape. At the debutante ball, he dons a formal, decorative knight ensemble.