Chapter 78 of Dorohedoro is the Fifth Chapter of Volume 13 titled: Curse 78 "Headbump-Ballad"
Summary
Inside En's Mansion the recently enrolled Cross-Eyes swarms the cafeteria while Ushishimada and Saji talks about the economic situation of the organization, even without Black Powder, they still have enough founds to give food and provide everything to their new comrades.
Elsewhere Tetsujo and Ton are testing the power of Natsuki's magic, seemly indestructible as she is able to repel every attack made by the ronin helmet Cross-Eyes. Ushishimada notes she would no longer need them thanks to her unique and powerful type of magic, but suddenly she dispels her magic showing her second tattoo in her right eye, and with conviction states she would never left them. Everybody is happy and cheers at her, except Tetsujo and Dokuga, showing serious concern.
Elsewhere in the new Zagan School Aikawa once again stole from the cafeteria and jumps to the roof of the building to slack like he always did in the past, with Risu tailing him from behind, knowing for sure he told someone about his magic, causing his death in the first place, but withouth notice Aikawa's Classmate appears and salutes Risu, exposing him and finally confronting Aikawa for everything that happened.
Risu scolds his friend for not know absolutely anything about him, where he lives, how he gets money and even his type of magic! Aikawa simply tries to ease the situation, infuriating Risu and triggering Curse out of pure anger. No longer believing a word Aikawa says, Risu goes straight to En's Mansion to force the Cross-Eyes to tell him exactly what he wants.
In Kawajiri's House, he and Nikaido goes through a smoke shower that transforms both into gender bender versions of themselves, along with a set of Cross-Eyes tattoos to sneak into En's mansion in order to find the ancient book of sorcerers with information about time-type Magic Users.
Back in En's Mansion while the top officers goof around the rooms of some En Family elites, a cross-eyes grunt informs them about a man who worked for them a long time ago coming their way, to everyone shock is Risu! Eager to hear some answers. Saji tries to make him understand that none of them knows who killed him, yet Risu states Dokuga knows things that they don't.
Risu transforms into Curse the monet Ushishimada tries to even think about attack him, while elsewhere, Aikawa sneaks into the Mansion looking for his friend. To his dismay he accidentally eavesdrop the conversation between Tetsujo and Dokuga, speaking about the powerful magic Natsuki have, and how the Boss will surely slaughter her for it. At the same moment Kawajiri and Nikaido enters in the room and Tetsujo puts them on check with his katana asking who are they and what do they want there.
Kawajiri commands Nikaido to fight them while he goes for the book, easily overpowering Tetsuji yet she finds difficult to fight with heavy clothes. Dokuga engages in the fight too and puts a lot of pressure on Nikaido, but he's knocked out when a statue of En breaks and its spiky stoke hair staves Dokuga's skull. Head bumping both and escaping from the room, she finds the disoriented Aikawa, obviously not recognizing her for her male body.