Anastasia met Echidna eleven years ago and Echidna became her consultant because she was intrigued by her. Echidna seems to care about Anastasia, as she possessed her body to protect her from danger in Priestella.
Echidna has known Ricardo for a very long time. He shortly played with Echidna by squeezing and stretching her to his heart's content until he was satisfied and let go of her. Even though Ricardo don't know much about Echidna, their relationship is somewhat decent.