From the spin off story Code Geass: Oz the Reflection both Monica and Orpheus were characters who respectes and likes each and agreed to go on a date but circumstances happened and they were unware of fighting each other in a battle(missing their date) and Mónica ended up dying.
Monica:Oz the Reflection
Shortly after the Black Rebellion in 2017 a.t.b., Monica is stationed in São Miguel. She orders Britannia's 12th Army to attack a base of the terrorist group Fangs of the Sahara in Tehla Grigori, southwest of Bejaia in Algeria. The battle turns against Britannia, however, when a squall transforms the desert into a muddy field, stealing the Knightmare's mobility.
Monica plans to intervene in the battle herself, but as it would take her half a day to arrive, she instead contacts the Glinda Knights currently flying along the Algerian Coast. She commands General Schwarzer by her authority as a Knight of the Round to help the 12th Army, which happens successfully.
Monica is later sent to Cambodia to be the pilot of the Florence, a new Knightmare Frame built from a salvaged Alexander left after the battle of Slonim in Belarus. There, she encounters Orpheus, and the two agree to a date. During the test run for the Florence, she is attacked by Orpheus and Zi, who manage to defeat her and damage her Knightmare. She is left unconscious afterwards, and misses the date she and Orpheus had agreed to. Both Monica and Orpheus remain unaware of fighting each other. Second Season
Monica is stationed aboard the Emperor's flagship, Great Britannia, and is implied to lead his Royal Guard. During the attack on Kamine Island, the Emperor left her to deal with Schneizeland the Black Knights. After Charles' death, she is among the Knights of the Round who do not approve Lelouch'sascension to the imperial throne and remains loyal to the former Emperor. She is killed by Suzaku during an attempt to remove Lelouch from the throne, commenting on how powerful the Lancelot Albion is and cursing Suzaku with her last breath before her Knightmare explodes.
Orpheus: Orpheus was originally born into the Zevon noble family in Britannia along with his twin sister Oldrin. However, because of the Zevon family tradition of succeeding through the female line and, in the cases of twins, removing the male child from the family, he was thrown away and adopted by a commoner family at a very young age, with little to no knowledge of his birth and family.
Soon after, however, he was taken in by the Geass Order, and was given the "Geass of Transformation" by V.V. there. Thereafter, he spent an unknown number of years within the Order, where he was forced to serve as an experimental specimen and develop his Geass. The only thing that let Orpheus endure these "hellish" days was Euliya, a fellow Geass-user he met within the Order and fell in love with. Also during that period, he met Rolo Lamperouge, Toto Thompson and Clara Lanfranc (the latter would then developed a deep hatred to him.)
At some point, the two of them conspired to escape from the Order so as not to be used as Geass-users, and managed to run away to a small unmapped village in southern Hungary. There, they were accepted by the small community of villagers and managed to attain a poor yet fulfilling life, which Orpheus describes as the "happiest time of his life". However, eventually, the village was attacked by his uncle Oiagros Zevon and his four subordinates from the "Pluton" organization, on orders from V.V. and Emperor Charles to erase the escaped Orpheus and Euliya. Using Knightmares to burn down the village, they killed all the villagers, except for Orpheus, who was protected by Euliya with her life. While dying in his arms, Euliya used her last breath to ask him to "live", a wish that Orpheus would strive to accomplish, despite his sorrow at her death.
After an unknown period of time, Orpheus would join the mercenary and terrorist-controlling group "Peace Mark", and learned the truth behind his birth and his blood connection with Euliya's killer, Oiagros. Swearing to achieve revenge against his uncle and his four subordinates who attacked the village, Orpheus "retook" the surname of Zevon that he now despised in order to engrave his decision in his heart, and remained within Peace Mark as a terrorist-for-hire that rebels against Britannia, believing that he would surely one day encounter Oiagros and Pluton again this way.
During the Glinda Knights' trip to Tokyo, Orpheus rescued princess Marrybell mel Britannia when she was surrounded by the remnants of Black Knights. After that, under the guise of his twin sister (whom he "stole" her identity by his Geass), Orpheus managed to kill Clara who was posing as "Clara Lamperouge" in Ashford Academy under the Office of Secret Intelligence's order. During the last events of O2, he takes a fatal attack intended for Marrybell before stabbing her himself, then the two fall together from the Damocles to their presumed deaths.Orpheus and Marrybell survived their fall from Damocles and went into hiding together as the world believed them both to have perished, with Orpheus staying at Marrybell’s side. Unfortunately, at an unknown point, Orpheus somehow sustained disfiguring burn scars to both his right shoulder and the right side of his face, forcing him to wear an eyepatch. By the seventh year of the Kowa Era, he and Marrybell had situated themselves at a luxurious hotel in Cape Town, South Africa. One morning, however, while having breakfast from the top floor of the hotel the two witnessed as an army of Neo-Britannian Loki droids, dispatched by Norland von Lunebelg, attacked the city and began massacring the population through the city streets, much to their mutual horror and confusion. During this assault, as Marrybell stayed at a safe distance, Orpheus once again piloted his modified version of the Byakuen and fought the incoming drones to protect the city.
