Secre is a short, slender young woman with a neat black bob, two rebellious locks sticking up from her crown, and dark shadows perpetually under her eyes. She wears a black dress with thin straps and a ruffled feather-like skirt, later adding the Black Bulls' robe. After training in the Heart Kingdom, her robe is secured by a grey cord. Two small black horns have grown from the sides of her head as a result of Forbidden Magic. Her expression rarely shifts, even when chaos erupts around her. She maintains a flat, deadpan demeanor and gets straight to the point with little regard for others' antics. When annoyed or needing to make a point, she pecks repeatedly at Asta's head or tugs his hair. Despite her blunt manner, she is fiercely loyal and rarely leaves his side.