WARNING: The following contains spoilers for Season 1 of Moriarty the Patriot, currently streaming on Funimation.
Code Geass and Moriarty the Patriot have a lot in common in terms of premise. They both center around people who feel they have been dealt a bad hand in life and around a group of people trying to get back at a bunch of nobles for doing horrible things. Both also feature power-hungry, corrupted stand-ins for the British Empire as their central villainous entities.
While Code Geass takes place in the future with giant mechs and advanced technology, Moriarty takes place in the 19th Century where technology wasn't at its peak. Both stories, however, are about very similar antiheroic protagonists who set out to dismantle the British-created systems that have held people down while rewarding the nobility who keep those systems in place.
Code Geass's version of Britain, known as Britannia, has taken over one-third of the world. The parts of the world under its control are designated by numbers, with Japan being "Area 11." Not only this, but the citizens of those areas are called "Numbers," so Japanese citizens are "Elevens." This takes away any autonomy on a national level, as well as a sense that they're their own people with their own culture and history. This version of Britannia follows the doctrine that the strongest survive, clinging onto Darwin's Theory of Evolution and the notion that competition and conflict are how countries grow in power. In Code Geass, the idea trickled down to British citizens, creating a classist society.
Moriarty's Victorian Britain is similar to that of Geass's in that it is also a classist society and a global power. There are no chances for people of the lower classes to rise up and gain a higher status. The nobility here is also largely corrupt, and use their status to get away with serious crimes like murder and kidnapping. They know that they can get away with their crimes, and so do the lower classes.
While classism is a real-life concept in British society (and others around the world) both of these series take it to an extreme. Even within Geass's Britannian Empire, there's a disparage between "purebloods" and "honorary" Britannians. The "purebloods" are descended from the nobility that fled to North America after Napoleon conquered the British Isles during the Napoleonic Wars. The "honorary" Britannians are the ones who were born in North America but were still loyal to the British Crown. Moriarty's nobility is probably the closest to real-life ideals, especially back in the 19th Century, in which it wasn't uncommon for people to get away with crimes because of their lineage. However, these crimes are highly exaggerated for the sake of the anime's story.
Lelouch was part of Geass's nobility. He was one of the noble children of the Emporer of Britannia who was exiled to Japan after he accused his father of not protecting his mother and sister. (His mother was killed while his sister was permanently left without the use of her legs.) He renounced his claim to the throne, resulting in his father exiling him. But Lelouch later uses his knowledge of the nobility and his siblings to take down the Empire alongside the people of Japan.
William James Moriarty was an orphan living with his sickly brother Louis in an orphanage where Albert James Moriarty, a high-born child, met them, befriended them, and convinced his father, Count Moriarty, to adopt them. William had witnessed the injustices of society since he was a child, and he talked to Albert about how he planned to change the way things are. Albert was so supportive of this ideal that he not only enabled him to be brought into his family but he also helped Moriarty and Louis kill his older brother, the real William James Moriarty, and burn down the family home, allowing the future Professor Moriarty to take the dead brother's identity. With his new identity, he increased his standing in society, enabling him to be able to set up situations in which victims of the nobilities' crimes can get revenge without being caught.
In the case of Lelouch and Moriarty, one is an insider fighting from the outside, and the other is an outsider fighting from the inside. Both are fighting for what they believe is justice against a corrupt empire. These empires do nothing to help those who society deems insignificant and those that have been put under their control by force. Classism is a way to control the masses, with those at the bottom viewed as expendable, making them feel trapped in a system that they will never be able to escape. In the fictionalized worlds of Code Geass and Moriarty, "purebloods" are deemed better than those of mixed heritage, even in the upper echelon. Should you step out of line, you will be made an example of, whether it's through exile, or being outright killed.
This is why Lelouch and Moriarty fight futuristic and historical versions of the British Empire, respectively. While Lelouch is more grounded in revenge for his mother and sister, Moriarty's revenge is for the lower class as a whole. In both cases, it seems that Britain just can't catch a break.
