Pino always played her hand held instrument in the key of C major.

Iggy is named after St. Ignatius of Loyola, a philosopher and figure known for extreme piety and loyalty.

Re-l Mayer's facial features have a very strong resemblance to the rock band Evanescence's vocalist Amy Lee from their debut album, "Fallen."

Ergo Proxy roughly translate from Latin as "therefore a substitute" or "therefore for an authorized agent acting on someone's behalf."

Most of the time Re-l Mayer sits with her left leg crossed over her right leg.

Ergo Proxy is not one of the 300 Proxies that were created in the Proxy Project. He was created by Proxy One.

Pino's journey through the storyline of Ergo Proxy is very similar to the story of Pinocchio - with Vincent Law taking the form of a very different Jiminy Cricket. Raul Creed can be assumed to be Gepetto since his last scene in the series is picking up one of Pino's drawings of their family and he smiles paternally, as if accepting that she became his true daughter, hence why Pino is short for "Pinocchio".

Daedalus Yumeno can be written as Yume no Daedalus. Literally "the dream of Daedalus". Daedalus was the father of Icarus and built him wings with bird feathers fastened with wax to escape from prison. But as Icarus flew too close to the sun, the wax melted and he dropped to death. Similarly, Daedalus' "child" Real Mayer (Monad reborn) flew to close to the sun and perished under the UV rays.

Vincent Law shares similarities with Vincent Valentine from the Final Fantasy series. They both wear a red coat over their bodies. They both have the ability to transform into a much powerful being.