He is gentle, formal, intelligent, and cares for his friends. Due to his frail health, he is frequently hospitalized. He comes from a major conglomerate family. While he appears kind to those around him, he is a true 'Emperor' who shows a ruthless side, willing to use any means to achieve his goals and even declaring he will 'crush' his enemies. He enjoys pranks more than he looks and hates being bored; to use Keito's words, he can be 'selfish' at times. Wataru also describes Eichi as being 'like a child sometimes.' In the 'Excitement! Heart and Blooming Mall Live' story, he even escaped from home behind his servants' backs and got lost, eventually meeting Sakuma Ritsu. He is described as a beautiful young man with a soft and gentle aura, sometimes even called 'angelic.' Despite being a high school student, he already seems to be handling some of the Tenshouin family business. Several stories mention him executing or investigating parts of the business his parents handed off to him. Notably, the Tenshouin family is said to hold a god-like position in the business world. Being born as the only son of such a family, he has grown up with immense power since childhood. His favorite food is veal sauté. Surprisingly, he is a meat-lover and dislikes sweets. Keito often mentions that Eichi's condition worsens during 'this time of year,' but the problem is that it's not just one season. His health seems particularly bad when the weather gets cold, and it's also poor in late summer. Since he's also prone to falling ill during the change of seasons, the phrase 'this time of year' is practically meaningless... It might just be that he's always in bad shape, and it's just a matter of whether it's slightly less bad or much worse. He has monologued about his cursed body, which is sustained only by medicine and IV drips. He speaks informally only to Wataru among the nurses. 179cm