If you're looking for anime similar to Code Geass: Lelouch of the Rebellion, you might like these titles. All recommendations are made by Anime-Planet users like you!
Years ago, humanity abandoned the ruined Blue World. Generations later, with the planet again capable of sustaining life, mankind returned. In the skies above the reborn world, rebellious young Fam and her best friend Giselle make their living as Sky Pirates. Atop sleek Vespa Vanships, the girls dart fearlessly through the clouds, capturing and selling airborne battleships for profit. It’s a life of care-free swashbuckling – until the Ades Federation attacks. The only nation to remain on Blue World during humanity’s exile, The Ades Federation wages war against those who returned only after the planet’s darkest days had passed. When Fam and Giselle rescue a princess from the clutches of the rampaging Ades armada, they join the young royal’s battle to save her Kingdom from destruction – and undertake the impossible mission of uniting humanity in peace.
Ten years before Shirou Emiya's and Saber's fateful meeting, Japan is the stage for the fourth Holy Grail War. Seven Masters, each with his own dreams, step forward to win the boon of the mystic relic. Into this fray comes Kiritsugu Emiya, the enigmatic "Mage Killer" who wants to use the Grail to make a better world. Can he, paired with the indomitable Saber win the War? Or will he fall to the ambitions of the other mages?
Both of these series involve loads of chracters making intricate plans against each other for various motivations. There is action and a supernatural element in both. Code Geass has a lot of high school age characters while Fate/Zero mostly involves adults, and there are more not-so-serious episodes in Code Geass. Code Geass has mechs while Fate/Zero has swords and sorcery. But they both have more plotting and gambits than you can count. If you like that aspect of one, you'll almost certainly like the other.
Hakaze, princess of the Kusaribe mage clan, has been betrayed and marooned on an island by her own people. They seek to revive the Tree of Exodus, an incomprehensibly powerful entity of alien origin, to save the world from the tyranny of its antithesis: the Tree of Genesis that powers their magic. Hakaze, however, believes their efforts put humanity in jeopardy; and with her power limited, she can only reach out to the world to beg for aid. Her call reaches Mahiro Fuwa, a young man grieving the mysterious death of his sister, Aika. He and his friend Yoshino agree to help - on the condition that Hakaze track down Aika's killer with her magic. The deal is made, and the battle that will determine civilization's fate is begun: but who will play the part of its villain, and who its savior?
They're both great animes with dark themes where the protagonists fight to right an injustice and an almost brother/rival relationship between the two male characters. They have complex characters where motivations are not always clear cut and events can turn the story on its head.
The characters are also similarly somewhat haughty and arrogant (CG - Lelouch, ZnT - Shakespear quoting lolita complex guy) anti heroes. I liked Geass a bit better due to its length but Tempest has a much more satisfying ending imo. Enjoyable animes both.
Fifteen-year-old Ichigo Kurosaki is a typical teen with fighting skills, two caring sisters and a special trait: he can see ghosts. However, when Ichigo and his family find themselves under attack by a huge beast, Ichigo discovers that there’s more to the supernatural world than the everyday specter. Vengeful spirits known as Hollows roam the world in search of devouring souls, and Shinigami – soul reapers – work tirelessly to defeat them and guide normal ghosts into a place called Soul Society. Ichigo valiantly fights the Hollow that threatens his sisters, but on the verge of defeat a Shinigami named Rukia gives him her powers, turning him into a Shinigami himself. Ichigo must now adjust to his new life of both vanquishing and saving souls for the sake of Soul Society.
In a mythical kingdom, the mighty Imperial Knights harness a magical substance known as Aer to power their weapons and protect humanity from the monsters of the forest. But something strange is afoot. The Aer is somehow changing, causing the wilderness to waste away and stirring the woodland beasts to attack with greater frequency. As danger creeps steadily closer to civilization, two young recruits - Flynn, the rigid son of a fallen hero, and the rebellious and brash Yuri - must ride with their fellow Imperial Knights to distant ruins in hopes of uncovering the truth behind the transforming Aer. Some will not survive the thrilling journey. Some will be betrayed. If Flynn and Yuri cannot overcome their differences and learn to fight together, all will be lost for the people of the realm.
Show may be different due to it's differences but the main Characters Lelouch and Suzaku's ideals and friendship are similar to Yuri and Flynn where Lelouch and Yuri wants to change from the outside and Suzaku and Flynn wants to change within. Both are awesome where it involves battles, politics, corruption, drama, blood, loss of allies, and friendship.