Ren♀

Ren Ren Ren Nagusaran Rensia Ruroonren Nakora, which can also be written '000-3901-0', better known by her short name Ren, is a young female DearS. "Ren" essentially means "nothing" in the DearS language, in reference to her being a "zero number".
Lost during shipment and freed from containment, Ren is found homeless by Takeya, who she immediately forces a covenant between and is subsequently given shelter by, much to his displeasure. Devoid of proper education, Ren is initially dysglossic and needy, but through curiosity and friends, becomes well versed in language and customs, even becoming admitted to Koharu High. As the self-proclaimed slave of Takeya, Ren is excessively altruistic to her unwelcome master, who prefers to view her as an equal than an inferior.
Ren's feelings and her own desires become progressively clearer as time passes, but she is constantly confused by those emotions and is unsure of their meaning due to the idea that DearS are incapable of understanding the concept of love. (spoiler hidden)