Codenamed Aves 11 in the Adamant Syndicate's experimental program, Lily May is the fastest-growing subject. Before her, the Adamant Syndicate had trained ten other test subjects.

According to a Syndicate member, Lily May is a light sleeper. She wakes at the faintest sound, making her perfect for night watch duty.

It's said that Lily May didn't know what rain was when she was young. When she first heard countless raindrops falling from the sky, she thought the camp was under attack.