Yotsuba Eisaku (四葉 英作) was the second Head of the , which is one of the . He took over after the death of his older brother, Yotsuba Genzou whom past away during the war with Dahan in order to avenge his daughter Yotsuba Maya. He made the plan to turn Shiba Tatsuya into a warrior and suppress his natural emotions to limit the dangers of him using Material Burst emotionally.