Spoilers ahead! One may not be aware of this when first starting out, but there is actually somewhat of a hidden fourth route when playing through Fire Emblem: Three Houses. When you choose the Black Eagles house, you are confronted with a choice, side with Edelgard and the Empire, or side with the Church of Seiros.
The choice you make has a serious impact on the game. Today, we'll be taking a look at the members of your team from the church of Seiros, and ranking them.
Rhea is last on the list because... well where exactly is she supposed to go on the list? Your view of Rhea and the actions that she takes are very dependent upon your view of her, as she isn't really a clear-cut good or bad person. Besides that, while she's incredibly skilled in battle from her stats, you never get the chance to use her as a playable character. Rhea is somewhat of an anomaly on this list, so she isn't necessarily last on this list because she's the worst member of the Church. Rather, she's here because there's no sensible place that she should go.
Hanneman is another one of the teachers at the Church. While he's a glass cannon of a battler early game, he quickly loses ground after the time skip, and presents no real reason to use him over someone like Overlord Lysithea. Beyond that, all of his support conversations center on crests, as they're truly the only thing that he cares about. Truly. Hanneman is just a skippable unit.
Cyril on the other hand... eh. He isn't great. Cyril isn't a holy person, and resides at the Church as a refugee of sorts. As lady Rhea was the one who saved him, he looks up to her tremendously, and would do anything to please her. Thus, he's constantly working, which makes all of his supports somewhat lacking. He's just not that interesting of a character. Battle-wise, he's good, but you really have to push him early game if you want to unlock his true potential, as he is kind of trash early on into the game. Cyril certainly shouldn't be on the top of your recruit list, to put it bluntly.
Gilbert's a bit of a mess. He abandoned both knighthood and his family many years ago, and feels incredibly remorseful and guilty for what he did. And he won't ever stop talking about it. So while basically all of his conversations are dedicated to how much of a trashcan he feels he is, he's pretty great in battle.
He's an absolute tank, and can take most hits with ease. Keep up with Gilbert, and you've got a great unit on your hands. Perhaps... an absolute unit?
Ranked this high on the list simply for personality alone, we have Manuela. The male version of Sylvain in just about every way, she's pretty mediocre on the battlefield while being a fantastic character off of it. All of her supports, ALL of them, center on her lusting after men left and right, to no avail. And drinking. What a life. All of her support scenes are a joy to watch, she's an absolute mess and it's wonderful. Depending on the route that she ends up on, her epilogues can be incredibly sweet, so pair Manuela up with someone that cares about her, please.
Catherine is one of the Knights of Seiros, and boy does she represent them well. She and her Thunderbrand can absolutely slice through enemies left and right, it's incredible to watch. Once her Thunderbrand runs out of energy, she's still a good unit, if not as overpowered as she once was. She's fun to talk to personality-wise as well. Her friendship with Shamir is fun to watch grow, and she truly cares about the rest of the Church-goers, including Byleth and the students.
And if you look on the right, you'll see the Church of Seiros's resident dad, Alois. Alois, another Knight of Seiros, Alois is incredibly powerful on the battlefield, and is very useful in most situations. He's an absolute monster if you choose to recruit him before the timeskip, so if you need a little boost in the early game, you know where to go.
Besides that, he's an incredibly jovial man that just wants everyone around him to be happy. He's constantly found cracking jokes left and right, even if most of them are pretty bad. He gives his all 100% of the time both in everyday life and on the battlefield, making Alois one of the best units that the church has to offer.
Shamir is the last Knight of Seiros featured on the list. Hailing from another land, Shamir originally was a mercenary, and started to work for the Church because Rhea saved her. She doesn't follow the Church's teachings, similarly to Cyril. She's a very dry person, and only says what needs to be said, though you'll learn more about her through her supports with various characters. Shamir is skilled with a bow, and is one of the best archers in the game. If yours is Ignatz... oops, lacking, Shamir is a great unit to switch them out with. Shamir is someone who might seem very cold on the outside, but you'll learn more about her as time goes on.
Seteth is one of the best units that the Church of Seiros has to offer. As a Wyvern Rider when you first recruit him, his movement is off the charts, and allows him to become one of your most valuable units, shooting left and right across the battlefield as needed. He continues to stay incredibly powerful throughout the course of the game. Personality-wise, he is an incredibly caring person. While he's a total helicopter parent when it comes to Flayn, he loves her deeply, and only wants the best for her. This man literally makes children's books with Hilda how can you not love him?
Flayn takes the number one spot on this list because she just deserves the world. She's incredibly sweet and caring, and simply wants to make friends and live her life to the fullest, all while supporting the church in any way that she can. She cares about everyone deeply, and wants to grow closer to all of them. While she's not the best on the battlefield, she is one of the best-suited units for the Dancer class, which in turn makes her one of the most valuable units in the game. All of these factors are why Flayn takes the number one spot on the list.