Momo Ayase, Okarun, and Aira Shiratori vs. Serpo Dover Demon Nessie is a battle that took place in Empty Space generated inside Kami High. Although hired by the aliens, Nessie treats his enemies and allies as one in the same like a wild animal, forcing the last surviving Serpo to merge with him and the Dover Demon. Now fused as the Serpo Dover Demon Nessie, they aim to eliminate Momo Ayase, Okarun and Aira Shiratori once and for all.
Prologue[]
Nessie was hired by the Serpo to help them keep Momo Ayase away as they steal Okarun's genitals, along with Aira Shiratori's who manages to enter inside Empty Space too after encountering Acrobatic Silky. After opening the pocket dimension, he makes his way to Momo's location and feels her presence through the water, prompting him to emit a highly destructive compression beam that cut all the classrooms' walls in half. Because he doesn't detect any more movements, he swims away while Momo stands up from her hiding spot and proceeds to regroup with Okarun.
The Dover Demon's jet punches incredible strength while in the water.
Later, as the three humans are facing the Serpo' trio and the Dover Demon, Nessie arrives to their location and turns the small layer of water into a giant barrier of water that replaces all the surfaces of the school into water. The Serpo are mad at his poor performance and threaten to cut their check when Nessie unexpectedly cuts one of them in half with a high-compression water beam. The humans try to flee but Aira is unfortunately hit by the shrimp's jet punch, throwing her into the ceiling and knocking her out. The Dover Demon informs them that his power increases tenfold in water, although he soon reveals that he doesn't have gills. After Momo and Okarun briefly argue about their relationship and what to do next since Turbo Granny apparently cannot swim, she has the bright idea to use him as a surfboard squeezed forward by her powers, jumping from the floor to the water ceiling and rescuing Aira.
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The Serpo Dover Demon Nessie spotting the trio.
Noticing a Serpo approach him, the Dover Demon apologizes and asks for more time when he's horrified by the alien's head, mauled in half by the monster. The last Serpo swims after the shrimp, pointing out that Nessie's tremendous power suffers from his indiscriminate attacks and the gig worker's inability to follow his targets because he cannot breathe underwater. With no other choice, he pulls out body cables from his skin to amalgamate with them and thus control their abilities. Meanwhile, the trio removes their clothes to have more freedom while swimming and hop on Okarun's back to navigate. As they descend, the Serpo Dover Demon Nessie spots them and engages in battle.
Battle[]
SDDN unleashing a high-compression water blast.
Immediately, the fusion powers up Nessie's high-compression water blast, directing it towards the trio who are able to dodge its path until the creature runs out of water, depleting the beam. Now back to an air pocket, they look down at the Serpo Dover Demon Nessie opening up its neck for water to flow inside, determining that it cannot fire its laser continuously. They decide to target it as to stop it from emitting any more water beams, so they dive down and Aira latches herself to the fusion with her hair to deliver a powerful kick. Before she can reach it, the monster throws a destructive punch her way, telling her that they do not only have a high-compression water blast in their arsenal but they are incredibly dangerous up close in spite of their appearance. Aira is catapulted skyward and the creature charges up another water laser, urging Momo to move Okarun out of the way and catch Aira as they swim by. The girl understands that the fusion has the Dover Demon's arms and it begins firing jet punches at a distance, forcing them to keep moving. Momo is furious as she realizes that the Serpo knew about Nessie's shortcomings and that's why they brought the shrimp along, with Okarun also being desperate about the situation, especially due to the water.
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Okarun going all out to save Momo, obliterating SDDN.
Hearing this, Momo suddenly realizes what to do but they are all flung away into the water due to a pressure punch and the Serpo Dover Demon Nessie approaches Momo. The Serpo is displeased that they have no more water to emit a blast, deciding that the best course of action is to immediately kill her and later dissect her, not even wasting time for her to drown as she's also a very dangerous person. Momo gestures at the monster, challenging it, so when it moves to crush her between its fists, she unexpectedly activates her psychokinesis to remove the large body of water around them. Due to the energy output of the mantis shrimp's only being fit for underwater usage, the shock generated while being in the air tears apart the Serpo Dover Demon Nessie's arms, which Momo reveals to the stunned monster. Yet, it lunges forward and tries to chomp her with its mouth which she struggles to hold open. The Serpo questions if she's going to either drown first or end up being obliterated by the high-compression water blast it is currently powering up with water. Out of nowhere, Aira's hair envelops the fusion, forming a straight road for Okarun to run on. Noticing its demise, the Serpo Dover Demon Nessie begs for its life before the boy goes all-out and grabs Momo, piercing through the monster's entire body and ending its life.
Aftermath[]
The trio interrogated by the nurse Queen after the battle.
Empty Space ends and the two lay together on the floor over each other's bodies, relieved that they can finally touch the ground. After laughing for a bit, they hear voices around them and to their shock, they are surrounded by the entire school who cannot believe what they have stumbled upon. In total embarrasment they dash away from the students' eyes, with Aira also trying to cover herself up and running towards the duo. They thankfully find shelter in the infirmary, home to the masochist nurse Queen who after asking if they were being bullied, she soon leaves to scold another teacher for barging in without knocking. Okarun makes a recap of the situation, stating that the aliens were after Turbo Granny's powers but they now could target Aira's Acrobatic Silky abilities too. Momo wonders why not just attack the yokai itself to obtain its power, leading Okarun to theorize that aliens do not have the necessary technology to overpower the spirits and the folklore creatures roaming and defending the planet, meaning they have to study special humans like them to achieve progress.
Later in the courtyard, Momo and Aira will be approached by the Dover Demon, stumbling forward to fight them. Still, his injuries after the fight are too severe to brush off and he collapses on the ground, so Momo decides to have Seiko check up on him back at their house.
Anime and Manga Differences[]
When Nessie arrives on the scene, instead of the entire floor suddenly turning into water, a huge wave shifts gravity from the ground, to the wall and ultimately to the ceiling, enlargening until they are all submerged. Only after that, the school and its walls become water.