Ophelia
The infamous number four of the seventy eight class, Ophelia harbors an incredible bloodlust, and particularly enjoys killing awakened ones. However, as she finds killing so unbearably fun, she has no qualms about killing humans as well, and takes great care to slaughter all witnesses, thus avoiding persecution by the organization.
Ophelia is an offensive type, and her trademark ability is “rippling” her sword by waving it back and forth with great speed, making it very hard to block or dodge.
Her hatred for awakened beings stems from an event in her past, where a certain Awakened killed her brother.
Her death on 8th volume can be a reference to literary work Hamlet (William Shakespeare). More specific, a reference to the paint “Ophelia” by John Everett Millais.