Rui is kind, curious, flirty, smug, teasing, possessive, genius, sly, and laid -back, human-like, and a very caring, gentle person over all who smiles a lot. Rui has been friends with Nene since childhood and made friends with Emu later. Rui is also terrified of Tsukasa because he's a prince, and his family will not miss the chance to eat or attack Rui. Even torture or capture.