E's (エス, Esu, often stylized E'S) is a Japanese shōnen manga series written and drawn by Satoru Yuiga. It was originally serialized in Monthly GFantasy from 1997 through 2005, and later published in 15 tankōbon volumes by Square Enix from March 18, 2003 to May 17, 2008. The series focuses on Kai Kudou, an "Esper", who is recruited by an organization called Ashurum to become a soldier to purportedly save other psychics from regular humans. After a mission in Gald goes wrong, Kai finds himself living with a man named Yuuki and his adopted sister Asuka. As he learns more about Ashurum, Kai finds himself wondering what their true goals are, and worrying about his ill sister, who is under Ashurum's care.

The series was adapted into a twenty-six episode anime series entitled E's Otherwise (エス・アザーワイズ, E's Otherwise) by Studio Pierrot. It debuted in Japan on April 1, 2003 on TV Tokyo; the final episode aired on September 23, 2003. Two light novels and three drama CDs related to the series have also been released in Japan.

Source: Wikipedia