Unkeen has a stout appearance, with the same gray colored skin of the Wicked Executives.He towers over other wicked yokai and has two sideways horns that curve up at the end. He has dark gray hair styled on a ponytail, and green eyes with fucsia sclera, with a shade of black surrounding them and going through his face as line-like marking. He also has two cattle-like horns on the sides of his head. He shares the same color scheme of the Wicked clothing, with a dark purple robe with a lighter shade of purple in a bull head-like pattern on his sleeves and a lining on the lower body, along with black hakama and a milky pink scarf covering his lower face and extending to his right side and black sandals with smoke-colored tabi. He sports the trademark Wicked flame on his right side, over his scarf.
His Japanese name, "Hakai" is a pun on "hakai" (Japanese: 破壊,"destruction"), with the latter kanji being replaced by "kai" (Japanese: 怪,"mysterious" or "strange"), which is a part of all Wicked Executives and Wicked Servants' names in Japanese.
His English name, "Unkeen" is taken directly from the English word "unkeen", and notably starts with "Un-", like all Wicked Executives' names in English.
His German name, "Verheerbert", taken from "Verheerung" ("calamity") and the name "Herbert".