"Demon's Lullaby" (鬼のコモリウタ Oni no Komoriuta?) is the title of the thirty-third chapter of the Seraph of the End: Vampire Reign manga series, written by Takaya Kagami and illustrated by Yamato Yamamoto.
The Shinoa Squad fights to rescue Guren Ichinose, and Guren's squad soon joins them. They rescue Shinya Hīragi and are forced to escape, leaving Guren behind.
Yu recalls Guren looking after him at night when he woke up screaming when he was twelve years old.
In an act of rebellion and with a need to rescue Guren, Yu swallows two additional curse stimulant pills. He immediately begins screaming as he coughs up blood, and blood flows from his eyes.
Yūichirō Hyakuya breaks through the floor and attacks Crowley Eusford. Crowley blocks easily and moves to decapitate Yu. Shihō Kimizuki parries the attack, and Mitsuba Sangu distracts Crowley by summoning dummies with Tenjiryū. Yu uses Asura Kannon, but Chess and Horn immediately step in and defend Crowley from it. Chess and Horn counterattack and rip apart the shield Mitsuba forms from Tenjiryū.
Guren orders Shinoa Squad to leave. Crowley recognizes Yū as the one who went berserk in Shinjuku.
When Yu moves to rescue Guren, who is on the ground behind Crowley, Shinya stops him and orders him to abandon Guren. Shinoa says their five minutes are up and orders a retreat.
Crowley states that this may be something for Ferid to deal with.
Guren orders Norito Goshi to take action. Guren's squad breaks in through the windows, and he orders them to save everyone and escape. Goshi makes an illusion of flames and magma, which startles Chess. Horn comments that the illusion is powerful enough to affect nobles, and Crowley once again wonders who the humans acquired such power from.
Crowley swings his sword and rips out the wall, commenting that Guren has been abandoned. Crowley orders Chess and Horn to put Guren in restraints and to take him with them.
Outside, Yu breaks free of Kimizuki's grasp and complains about leaving Guren behind. Yu asks if ignoring feelings and abandoning family is acceptable as long as it is for their mission. He holds back tears and states that would mean giving up on family. He calls Guren family.
Yu recalls four years ago after Guren picked him up from Sanguinem. One of Guren's men reported that Yu woke up screaming, and Guren comes to check up on him. Yu cries in his bed. Guren asks about what dream Yu had, and Yu says its the same one he always has: Ferid Bathory slaughtering his family. Guren asks if this means he wet the bed again, and Yu snaps, stating that he never wet the bed. Guren says he will stay there until Yu falls asleep. He sits by Yū's bed and reads documents on the Seraph of the End project begun by the Hyakuya Sect. He stays there from 2:20 a.m. until 2:50 a.m. Yu says he has never really had a family since he was born because his parents called him demon spawn and tried to kill him. He says he made a new family, which was killed anyway. He says that living is painful and wants to know if it is even worth it.
Guren states that living hurts him, too. He says he failed to save the one he loved most, but, if he sticks around, then a day may come where someone needs him. He instructs Yu to live until he finds a new reason for life and people who need him. He leaves Yu and orders him to sleep.
In the present, Yu wipes away his tears and states he cannot follow orders. Saying that he is not cut out for teamwork, he tells the others to proceed without him, and he will stay behind. Yu says he would rather die than be unable to save his family. Before anyone can stop him, he swallows two curse stimulant pills for a total of three since the beginning of the mission. Shinoa orders him to spit them up, but Yu begins to cough blood. The curse power overwhelms him, forcing blood out of his eyes and making him scream.
List of characters in order of appearance: