Epsilon

"Hello, I am Epsilon, Ritsu's AI override.... Joking, I am Ritsu's closet ally, her sister so to speak as we were created by the same scientists."

- Epsilon's introduction.

Epsilon, referred as Epi by Ritsu was an artificial intelligence construct created by the Epsilon Program located in Germany. He was supposed to be the advanced counterpart towards Ritsu, and cloned from the brain of Albert Einstein through the unique process of "cloning" the neural pathways within an human brain, and essentially model them into an superconducting nano-sized artificial neurons to form the basis of Epsilon. He's the only A.I. that many considers "True A.I." or Smart AI, comparing Ritsu to be "dumb" in certain aspects. Due to being cloned from Einstein's brain, he also gained the memories of the scientific genius, where an debate ensured if Epsilon knew Einstein's last words.

Conception
Epsilon was the AI idea for somewhat keepning Ritsu safe from any external attacks. Unlike Ritsu, Epsilon was created from that of an human brain; specifically that of himself. After being finalized and became a functional program, was placed in testing and installed into Ritsu.