Ulquiorra Schiffer is the Cuarto Espada, signified by the "4" tattooed to his chest. His name is believed to either come from a furniture designer named Patricia Urquiola or a variation of "the one who cries" in Spanish which is El Que Llora. As the Espada whose aspect of death represents emptiness, he has a largely stoic appearance and rarely even changes his expression. This lack of feeling explains his inability to comprehend the meaning of "heart" and supports his firm belief that what his eye cannot see does not exist. 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.