Seraph of the End Thesis

In the fictional world of 2012, the world allegedly comes to an end at the hands of a "human-made" virus, ravaging the global populace and leaving only children under the age of thirteen untouched. It is at this time that vampires emerge from the recesses of the earth, likely followed by age-old horrors of the dark thought only to be myth. The vampires sweep the earth and claim it in a single violent stroke, subjugating the remnants of humanity and leading them beneath the surface to safety. This "protection" comes at the price of donating blood to their captors. At the age of twelve, Yuichiro and his friend and fellow orphan Mikaela plotted to escape along with the children in Hyakuya Orphanage. However, this resulted in their deaths and Mikaela sacrifices himself in order for Yuichiro to escape and be saved by members of the Moon Demon Company, an extermination unit of the Japanese Imperial Demon Army. Four years later, Yuichiro dedicates his life to destroy vampires and seek revenge against them for murdering his "family".

Sounds similar to another anime, doesn't it? What if I told you, there is a theory--or more--that surround this anime. Yup, have a good time with this. 

Seraph of the End is a Lot Like Attack on Titan: OK, this is gonna get a lot of hate from other people who are fans of this series. But Attack on Titan and Seraph of the End are similar to one another. There's vampires and Titans aside that attack humans but that's not it! Most of the characters have been compared to similar ones in Attack on Titan, especially Yuu to Eren (both are Hot-Blooded with a goal of killing all the monsters who killed someone dear to them when they were children), Kimizuki to Jean (both start as Jerkasses who the protagonist despises but are later revealed to have Hidden Depths and become Fire-Forged Friends with the protag), and Guren to Erwin (both Colonel Badasses who have their own goals independent of the main military branch). It helps that both series share similar premises, the same animation studio, and the same soundtrack composer. However, whether this trope is interpreted as "similar, but still unique and good in its own way" or "blatant ripoff" depends on the viewer. But remember, they are different with monsters such as the Horsemen, vampires, and Titans for both each of the animes you see. OK? Nothing! Nada! Zip! Zilch! No ablo relations or rip offs! OK? OK, good let's move on shall we? 

Yu and Shiho are Bi: There are some hints that they could be, while Yu and Shiho are attracted to girls but they could be attracted to guys too! Yuu's constant mention of Mika is also something to take note of. He can't go a single chapter without mentioning how he's also going to save Mika from the vampires. There is literally TONS of examples of their obsession with rescuing/being with each other, to the point where other characters (like Ferid) even comment on it. Yuu immediately begins to shed his antisocial demeanor after seeing Mika alive, where Shinoa even states that after that moment his reason to live had changed. In chapter 39, Yuu's hatred towards the vampires (at least towards the vampire queen) is immediately forgotten when he learns that she was the one who saved and kept Mika alive, stating that he's thankful to her for bringing them together and then expresses his willingness to trust her. Yes, that Yuu who holds a grudge as deep as the Mariana Trench against vampires is thankful to the leader of his sworn enemies just because she saved Mika. The creator, Takaya Kagami, refers to Mika as "the one who suddenly died, the wife!" at the end of volume 1, which certainly has it's implications. In the manga and drama CD, Shinoa questions Yuu if the name he had called out was his former girlfriend. Yuu doesn't deny this, but rather corrects her that Mika isn't a woman. Yuu holding Mika's face, touching his chin and looking at him in a flirtatious and almost cocky manner. Before, they backed up into some shelves when Mika glomps him so he can drink from his neck, all the while smiling blissfully and holding the back of Mika's head while Mika himself is holding onto the shelf as well as Yuu's spread open knee. While toward the end of the episode it has Yuu hugging Mika from behind and a shadow silhouette showing them holding hands as they walk away. With the sun setting in the background no less. While Mika is on top of Yuu after a failed attempt to drink from him, Yuu pulls his head closer into a hug while apologizing for his leaving him behind in the past. At the beginning of chapter 37, there is a close-up of Yuu blushing while Mika is drinking from him. When Mika finally pulls away, it's shown that Mika has been as well. The creator even states that Yuuichirou and Mikaela are like Romeo and Juliet, ooh a yaoi version of Romeo and Juliet huh. Nice! Also; Kimizuki gets a Chained Heat moment with Yuu in the manga, acts especially tsundere towards him, and carries/watches over him when he's injured or unconscious. There's one scene in episode five where they are getting really close to each others faces when arguing and Yoichi's head is blocking their faces almost making it look like a Kissing Discretion Shot. They have moments where they get along and Yuu praises Kimizuki for being awesome while blushing when he learns he can drive and hot wire a car. Kimizuki blushes in response to this. At one point in the manga, Shinoa jokes that Kimizuki "swings that way" to the rest of the squad. Yoichi reacts with, "He does?!" while blushing. And add some light hearted-ness; Shinoa and Mitsuba tease them about their relationship by comically impersonating Kimizuki and Yuu as lovers, complete with blushing and a passionate embrace. Funny yet yaoi fangirls' dream come true! 

Mika is Gay: That explains it, right? Mikaela's obsession with Yuuichiro, full stop. He tears off a noble's arm  for trying to drink his blood, nearly makes off with him in a Bridal Carry in chapter 13, and has convinced himself that Yuu's human allies are just using him in order to justify his taking him back. There's the way he seems to get jealous of Shinoa in general especially when she gets Yuu in a Cooldown Hug. He ends up screaming at her "Don't touch Yuu with your filthy hands!" Both openings of the anime show the two touching foreheads with their hands cupping each other's cheeks. In episode 3 a vision of Mika hugs Yuu from behind and caresses his face. At the end of episode 12, Yuu and Mika look up at the moon, thinking of each other while miles apart. Yuu places his forehead against the glass window where an image of Mika is reflected in the same position. Then, with a determined look in their eyes, they mutually declare to save each other.

Yoichi is Gay: He doesn't seem attractive to other girls but I could be wrong! Yoichi acts very friendly around Yuu, glomps him in the manga and waiting by his bedside for him wake from from passing out implying he was watching him, and gets very blushy around him. In episode 2 dub of the anime when asked who Yoichi was, Shinoa's answer was: "A friend of his, or a lover." This occurs when she is observing with others as Yoichi lays on top of Yuu in between his legs after glomping him and shaking as he is crying while holding on to him. From Shinoa's and others angle it looks very suggestive. Yuu gets moments where he acts very concerned about Yoichi's well-being when they're in battle, and strives to save him from danger occasionally.