Yesod's personality is strict, uncaring and logical, but sometimes, he limits himself when he 'overacts'. He examines each situation meticulously and logically, believing that emotions and trust for his employees are unnecessary. Still, he tries to keep casualties minimized through prevention. He has a complex hallucination that causes him to always stay covered up, not revealing much of his skin or body besides his own head. Any type of description of him by other workers, like 'devoid of emotions, cold-blooded...' are taken as compliments by him, because he believes that personally knowing someone or feeling emphatic can make his own employees exploit him.