 Bent on completing tasks set to him by Sōsuke Aizen, Ulquiorra has no qualms about attacking his own allies if they impede his intent and deems anyone he finds not to be of particular interest to be "trash," and therefore expendable.The remainder of Ulquiorra's hollow mask, partially destroyed before his conversion, forms a broken helmet with a curved horn and covers the left half of his head.His hollow hole has moved since his first appearance; when first introduced it is at the base of his neck, but in later appearances, it is centered just below his collarbone.