Katsuki Bakugo, Shoto Todoroki & Fumikage Tokoyami vs. Moonfish is a battle fought between Class 1-A students Katsuki Bakugo, Shoto Todoroki and Fumikage Tokoyami against the villain Moonfish during the Vanguard Action Squad Invasion.
At the start of the Vanguard Action Squad's invasion, Moonfish attacks Fumikage and Mezo in the forest. Mezo saves Fumikage from Moonfish's tooth blades but gets one of his Dupli-Arms cut off. Fumikage's grief and negative emotion fuel Dark Shadow until it goes berserk and breaks free from Fumikage's control.
Shoto realizes there must be a villain using his Quirk to produce the gas and worries about his friend's safety. Shoto thinks must entrust their peers' safety to Ragdoll and head back to camp. His partner, Katsuki ignores him and tells Shoto to stop walking in front of him.
Soon after, the duo encounters Moonfish kneeling over Mezo's severed arm, appearing to appreciate the severed flesh. They're surprised and Katsuki asks which group was in front of them. Shoto says it was Fumikage and Mezo. Moonfish turns his attention to the students and warns them not to tempt him because he has a job to do. Itching for a fight, Katsuki asks if Mandalay is sure she meant no attacking the villains. 
Mandalay sends out a telepathic message granting students permission to fight the invaders. Shortly after, she sends out another message saying that Katsuki is the villains' target. Katsuki runs at Moonfish and says he could focus on taking care of himself if Mandalay got out of his head.
Moonfish suddenly sends Tooth Blades shooting out at Katsuki, taking him by surprise. Shoto acts quickly and freezes the ground to create a shield of ice that protects Katsuki. He warns Katsuki not to recklessly rush into a fight.
Moonfish suspends himself in the air by balancing on his enlarged teeth. Katsuki is annoyed that Mandalay said not to fight and then changed her mind because he has a feeling Izuku is involved. He tries to attack again but Moonfish's teeth enlarge and impede his path. Shoto expands his ice and tries to freeze the villain but Moonfish dodges and jumps into the trees. Aggravated, Shoto says Moonfish is good at moving through the forest with his Quirk and surmises that Moonfish is a seasoned fighter.
Katsuki says Moonfish looks like a weakling and starts gearing up his explosions. Shoto reminds him that they can't start fires because their classmates could die inside the forest as a result. Shoto mulls over the fact that even if they retreat there is still poison gas to their rear. He knows the villains have all the students cornered.
Meanwhile, Izuku Midoriya searches the forest for Katsuki and nearly gets hit by a shadow claw when he is dragged out of the way. Mezo saves Izuku and carries him on his back to protect him from the shadow. Mezo says that Izuku should be recovering from his injuries but he knows that he wants to save Katsuki from the villains. Izuku replies that Mezo is injured too and the latter explains he and Fumikage were attacked by Moonfish, and after seeing Mezo Hurt, Fumikage lost control of Dark Shadow. Izuku realizes in horror that the shadow claw came from Fumikage, who is painfully attempting to restrain the Dark Shadow.
In order to get to Katsuki they will need to get through Dark Shadow first. Izuku quickly realizes the dire situation Fumikage is trapped in. Fumikage watches from the clutches of Dark Shadow and warns his friends to run away or else they might die.Dark Shadow attacks indiscriminately at any sound. Mezo plans to lead Dark Shadow back to base camp in order to weaken it with light. He refuses to leave Fumikage behind and tells Izuku he'll distract Dark Shadow if he wants to go ahead to save Katsuki.
Izuku points out that Mezo is taking a big risk. Dark Shadow hears him and attacks. Mezo dodges as Dark Shadow breaks the tree they were hiding behind. He tells Izuku that heroes take risks and that he must choose between saving Katsuki or Fumikage. Izuku answers that he wants to save them both. He devises a plan to lead Dark Shadow towards Katsuki by using Mezo's Dupli-Arms to create mouths that bait Dark Shadow so that it doesn't attack their real bodies.
Moonfish continues his assault and barrages Shoto's defenses with his bladed teeth. Katsuki is annoyed by the teeth attacks and states he wants to attack with maximum firepower. Shoto reminds him not to and Katsuki replies to cover the trees with ice if they burn. Shoto points out a big explosion may impair his vision and make him unable to see the fire.
The battle is interrupted when suddenly Katsuki, Shoto, and Moonfish notice A series of rumbling blasts coming for them. it turns out to be Mezo and Izuku leading Dark Shadow toward them. Mezo pleads for one of them to make light to control Dark Shadow. Moonfish tries to attack but is quickly crushed by Dark Shadow's claw, shocking both Katsuki and Shoto. They both notice their three classmates and Shoto puts down Kosei.
Shoto says he'll create light with his fire to stop Dark Shadow but Katsuki tells Shoto to wait. Moonfish picks himself up using his teeth and demands Dark Shadow stop stealing his prey. The villain attacks with his bladed teeth but Dark Shadow easily immobilizes with its claw. Dark Shadow says Moonfish is nothing but an insignificant bug and crushes him in its hand, breaking most of his teeth. Katsuki watches on in delight and says Dark Shadow must finish him off. Dark Shadow slams Moonfish through several trees and throws him across the forest, defeating the villain in an instant.
Dark Shadow continues to rage and desires to create more havoc. Katsuki and Shoto swiftly activate their Quirks and run beside Fumikage. The light produced from Shoto's fire and Katsuki's explosion clams Dark Shadow back into its weakened state.
Katsuki says that he's still a terrible matchup for Fumikage and the latter thanks his peers for rescuing him. Shoto commends Fumikage's strength because he defeated Moonfish instantly even after they struggled to defend themselves at all.
Fumikage apologizes to Mezo and Izuku for losing control of Dark Shadow. Mezo forgives him and asks him to move on because that's what Fumikage would do if their roles were reversed. Izuku reminds everyone that the villains are after Katsuki and devises a mission to get Katsuki back to base camp. Izuku says they should cut straight through the forest and take the shortest route back to camp. They establish the Bakugo Escort Squad and decide to use their Quirks in case they come across any villains. Katsuki believes he doesn't need protection and gets upset, but his peers surround him as they walk anyway. 
|Forest Training Camp Arc|
|Chapters||70 • 71 • 72 • 73 • 74 • 75 • 76 • 77 • 78 • 79 • 80 • 81 • 82 • 83|
|Volumes||8 • 9 • 10|
|Episodes||39 • 40 • 41 • 42 • 43 • 44 • 45|
|Battles and Events||Class 1-A Swimming Competition • Quirk Training Camp (Class 1-A vs. Pixie-Bob) • Vanguard Action Squad Invasion (Tiger & Mandalay vs. Magne & Spinner • Izuku Midoriya vs. Muscular • Eraser Head & Vlad King vs. Dabi Doubles • Tetsutetsu Tetsutetsu & Itsuka Kendo vs. Mustard • Katsuki Bakugo, Shoto Todoroki & Fumikage Tokoyami vs. Moonfish • Ochaco Uraraka & Tsuyu Asui vs. Himiko Toga • Momo Yaoyorozu & Yosetsu Awase vs. Nomu • Bakugo Escort Squad vs. Vanguard Action Squad)|