"Complicated Connections" (工作するカンケイ Kōsakusuru Kankei?) is the title of the fifteenth chapter of the Seraph of the End: Vampire Reign manga series, written by Takaya Kagami and illustrated by Yamato Yamamoto.
Mika wakes crying during his detoxification back in Sanguinem. Lacus Welt and René Simm attempt to get information from him about Yu and mention the "Seraph of the End." Mika divulges nothing. Third Progenitor Krul Tepes calls Mika to her chambers.
Yu wakes up in the hospital. He cries from happiness when he recalls that Mika is still alive.
In Krul's chambers, Mika promises to save Yu. In the hospital, Yu promises to save Mika.
Ferid hands over research data to his partner in crime.
In Sanguinem, Mika wakes up once his curse detoxification is complete. Wiping away his tears, he mentions that he has not cried since becoming a vampire. While getting dressed, Lacus attempts small talk with Mika, but Mika remains silent. Lacus and René talk about the monster on the battlefield and mention how it troubled the Progenitor Council. Lacus mentions how the humans were performing forbidden research that could destroy the world, which was something called the "Seraph of the End."
Lacus tries to get information from Mika. He says that human monster was someone Mika used to know, and he asks if that was why Lady Krul favors him. He asks Mika what exactly Mika is, to which Mika answers, "That's easy. All you have to do is look at me. I'm just an ugly blood-sucker."
Third Progenitor Krul Tepes summons Mika to the Royal Audience Chamber, and Lacus calls Mika the queen's pet.
In Shinjuku, Yu finally wakes up in the hospital after a week. He wakes up Yoichi, who is sleeping at the end of his bed. He asks what happened, but Yoichi is overly-excited and goes of to inform the other members of their squad first. Yoichi says that Yu was the only one who was badly injured and spent a week in a coma. Yu realizes that Mika was really alive after all, and he cries tears of joy right in time for Shinoa to show up and tease him.
Yu does not remember anything after Mika asked Yu to run away with him. Shinoa tells Yu that he suddenly collapsed on the battlefield. She says that quite a few non-noble vampires were killed, with a handful captured, but over half escaped. Yu asks about Mika, saying that he does not care if Mika were the enemy or an ally. Shinoa says that Mika refused to leave Yu's side until another vampire physically dragged him away. She advises him against any stupid rescue attempts, and Yu says that he is not that stupid and is happy enough knowing that Mika is alive for now.
The rest of Shinoa's squad storms in. Yu apologizes for making them worry, and he says that he is glad everyone survived. He tells them he is blessed with great friends. The squad asks him if something is wrong with his head. They then inform him that they are on leave until Yu is approved for battle again.
In the queen's chamber, Mika promises to Krul that he will save Yu. In his hospital bed, Yu swears he will save Mika.
Meanwhile, on a rooftop in a desolate ruined cityscape overloaded and filled with sand, Ferid is amused that everything is proceeding so perfectly that it's almost laughable. He says that humanity's all-consuming greed continues to expand unchecked and the vampires' boundless arrogance has them looking down their noses at the entire world. He turns and asks if his ever-so-amusing partner agrees. Ferid hands over a box of research data to the partner.
List of characters in order of appearance:
Manga panels provide a visual overview of the events of Chapter 15 with depictions of the characters, Seraph of the End world and scenarios.