FranXX, giant mechas, are the only weapons capable of combating the Klaxosaur, an invading species of giant beasts bent on wiping out humanity. Humans are now clustered in walled cities called plantations, and there, children are raised solely to be able to pilot the giant mechas and fight back against the Klaxosaur. A young boy named Hiro has goals to one day pilot a FranXX, but those are in jeopardy when he fails a test; however, a fated meeting with Zero, an infamous FranXX pilot, may change his fate. To pilot a FranXX, you need two pilots: a boy and a girl, and Zero Two’s earned a name for herself as “Partner Killer”. All of Zero Two’s partners have wound up dead and this instance is no different, but when the Klaxosaur suddenly invade their plantation, Zero Two needs a new partner and turns to Hiro. Surprisingly enough, Hiro turns out to be the perfect fit and sees this new partnership as his chance to redeem his dreams.

The core narrative of coupling to control a giant mech in order to combat a race bent on humanity’s destruction is identical in Sousei no Aquarion and Darling in the Franxx. In both series, the male leads are thrust in the position of protecting humanity through these giant mechs and that protection revolves distinctly around their ability to synchronize with a fellow female pilot. These two series also deal with young adults raised and taught for the sole purpose of manning giant mechs and uniting to combat the invasive aliens. As with Sousei no Aquarion, Darling in the FranXX has a decently sized cast and episodes get around to giving many of them spotlights as they also learn to synchronize with their partners. Darling in the FranXX and Sousei no Aquarion are also unique for the way in which the characters activate the mechs in a very sexually euphemistic way.

Renton Thurston, a 14-year-old boy, lives an ordinary small town life with a desire for more. His grandfather expects him to follow in his footsteps and become a mechanic but the legacy of his deceased father – a man who supposedly saved the world - looms over him. To add a little thrill to his life, Renton spends his free time riding a board over Trapar particle waves, essentially surfing over the air. One day, a giant mech called a Light Finding Operation crashes into his home and a girl by the name of Eureka comes out of it. She requests that they fix up the Nirvash, her mech, and he discovers that she’s a member of the mercenary group he idolizes, Gekkostate. Renton Thurston finds himself joining the mercenary faction Eureka belongs to and co-piloting the Nirvash alongside her.

Eureka Seven checks just about every box you might want. The series’s unique surfing robots add a layer to the already great combat scenes in Sousei no Aquarion. From the get go, you’ll also know Eureka Seven has a strong romance between Renton and Eureka; however, there’s much less friction between the pair than there initially is between Apollo and Silvia. And of course, as with Apollo and Silvia, Renton and Eureka are co-pilots of their mech. If you enjoyed the twist and complexities from the end of Sousei no Aquarion, then you’ll find plenty of those in Eureka Seven, including a decently-sized cast with many of them given a chance to shine across the series’s fifty episodes.

During the construction of the Kurobe Dam, an ancient artifact was discovered and the United Nations Kurobe Research Institute gathered scientists from around the world to study it. Yukina Shirahane, the main character, is a high school student, and the daughter of the head scientist in charge of the study. When she goes to visit her mother at the facility, she manages to unlock a piece of the artifact’s puzzle, but what comes out isn’t quite what she, or anyone, expected: a samurai from the Sengoku period called Kennosuke Tokisada Ouma. Kennosuke installs himself as Yukina’s protector, and together, they co-pilot a mech to combat an invading alien force.

The immediate difference between Kuromukuro and Sousei no Aquarion is that Kuromukuro is largely from the perspective of a girl being thrust into war instead of a boy. Although Ouma is the man out of time, it’s Yukina who is in a situation bigger than she could’ve ever imagined. Aside from that, we’re getting many of the same elements from Sousei no Aquarion, like the presence of an alien invading force, mecha co-piloting, and high school aged teens defending humanity. Not to mention, that alien invading force is a returning threat that was once defeated in the past, and like Sousei no Aquarion, what happened in that past is tightly linked with what’s happening now. Kuromukuro will dish out the big cast, the relationship between the male-female protagonist pairing, and some incredible giant mech action sequences to get you everything you might have loved from Sousei no Aquarion.

Aoba Watase, a high school student, has his world turned upside down when a giant mech appears out of nowhere and attacks him. He’s saved when one of his classmates, Hina Yumihara, equipped with a giant mech of her own, arrives to fend off the attack. Aoba discovers that Hina and the giant mech are actually from a war-torn future, one Hina makes Aoba forcefully join. In the future, the Free Pact Alliance and the Zogilia Republic are at war and use giant mechs called Valiancers as their primary weapons. Aoba finds himself in the middle of this war within a Valiancer of his own and quickly synchronizes with a Free Pact Alliance pilot called Dio Weinberg. Through coupling, Aoba and Dio are able to enhance their piloting skills. Of course, there’s the issue that Hina isn’t a member of the FPA but of the Zogilia Republic, and now, Aoba finds himself caught in the middle of a war he doesn’t yet understand.

Buddy Complex follows the general mecha initiation of a boy dragged into a war much bigger than him but who demonstrates unusual aptitude in piloting a mecha and the capacity to turn the tides. As with Sousei no Aquarion, coupling is the key to changing the course of a battle, and the war at large. In this case, Aoba differs from Apollo in that he’s coupling with another boy, and romance isn’t a predominant part of the story. Buddy Complex has a layered narrative behind it, with many questions that get answered overtime much like Sousei no Aquarion’s own mysteries. However, if what you’re after is just the mech action, then don’t worry, you’ll get plenty of that in Buddy Complex.

Simon lives in a small village underground and the surface is nothing more than a myth to him and his fellow villagers. He spends his days drilling and excavating deeper and deeper underground for whatever he can scavenge. Kamina, another boy in the village, aspires to go to the surface and isn’t content with their lot in life. One day, Simon discovers the key to a mech they come to call Lagann. The discovery proves to be timely when their village is attacked by a Gunmen, a giant robot controlled by the Beastmen, creatures that have taken over the surface of the Earth and forced most of humanity underground. With the help of Yoko Littner, a girl that travels the surface with gun in-hand, Simon and Kamina use Lagann to fend off the Gunmen and begin wandering the surface of the Earth themselves.

Tengen Toppa Gurren Lagann definitely stands out from its fellow mecha anime genres, especially Sousei no Aquarion, which is steeped in tradition, but it nevertheless contains the same sort of world you’d find in Sousei no Aquarion. Gurren Lagann’s human race has been pushed to near extinction and finds itself constantly threatened by a far more dangerous species. There is no coupling or merging at the forefront but we still see Simon inside of the Lagann with both Yoko & Kamina joining him. Furthermore, you’ll be treated to some of the most insane and over-the-top mecha action you can find and the same humanity-against-extinction plot you’ve come to appreciate in Sousei no Aquarion.

Sougo Amani, a young miner in the world of Gift, gets more than he bargained for when instead of finding the rare Giftium crystal, he finds a girl by the name of Felia. Felia’s identity and past are a mystery, but her abilities make her the target of an organization hellbent on using her powers for their own purposes. Felia’s abilities are linked with a mech that shows up when she is in danger and that remains a core mystery until the end of the twelve-episode series. Comet Lucifer follows Sougo and his friends as they try to keep Felia away from her pursuers while also uncovering the mystery behind her. In their frequent encounters, the mysterious mech associated with Felia helps to fend off the antagonist’s own skilled pilots and their mechs.

Like Sousei no Aquarion, Comet Lucifer centers around the budding friendship of a group of young adults – though Comet Lucifer’s cast tends to be slightly younger – and a mysterious mech they can’t quite understand but need to master to combat overwhelming forces. In both series, the core relationship revolves around a boy and a girl; in Sousei no Aquarion its Apollo and Silvia, and in Comet Lucifer its Sougo and Felia, but Comet Lucifer’s romance is heavily downplayed. If you really enjoyed Sousei no Aquarion’s CGI action sequences, then this is the void Comet Lucifer will best fill with much improved CGI and some great mech battles throughout the short series.