SMG4: World War Mario is the twentieth episode of Season 9 and the five hundred and first overall to be uploaded by SMG4.
This episode sparked the beginning of the Battle of Anime Island. This is also the fourth episode of the 2nd part of The Anime Arc, as well as the eleventh and penultimate episode of the arc overall. It was aired on June 1st, 2019.
The video starts off in the early morning of June 6, 2019, near the coast of Anime Island. Troop transporters, carrying most of the former A.S.S. personnel, as well as the SMG4 gang, are on their way to the shores. While Mario is singing, some others are worried (with Fishy Boopkins carrying medical supplies and Tari bringing a telephone, nervously). Meanwhile, Swagmaster is seen boasting on how he's ready to beat up some anime while Bob Bobowski reads a headline from the Daily Globe.
Tari starts to sob in fear, refusing to believe that their mission to save their friends has grown into a full-scale war. Saiko reassures her and the others that they are finally arriving to save Meggy. Suddenly, they hear Luigi panicking, stating that he can't take it and wants to be let off from the battle. Mario then reassures him that everything would be okay and asks one of the agents about it. The agent answers that they are doomed, and Luigi's attitude only worsens. Chris, the commander of his squadron, announces that only 30 seconds are left before their boat finally reaches Anime Island, and tells his mates to clear the bunkers and try their best to get off the beach if they can. He then wishes good luck to all his mates and hopes that God will be with them.
As the boat's door opens (with Swagmaster telling Chris that he's scared and Chris replying that he's scared too), the Anime Cartel forces begin to open fire at the boat, killing most of the A.S.S. agents instantly, leaving Mario, Luigi and SMG4 to scream in terror as they get off the boat. As Rem and Jojo fire their machine guns at them, Saiko deflects the bullets away with her hammer and tells Tari and Fishy Boopkins to start moving right now. Meanwhile, Mario (holding a corpse) and SMG4 (who is swimming on the waters) make their way towards the shore, while many A.S.S. agents are being killed in gunfire and explosions. As they run to the nearest barrier, Mario asks SMG4 about how his Thursday was, with him screaming in reply.
In the middle of the carnage, a shocked Fishy Boopkins stands as he quotes the "War... war never changes!" line from the Fallout series. Meanwhile, Bob tells the anime forces to go back to their mangas and anime while shooting behind a metal barrier, when suddenly Karen Kujou pokes out and shoots Bob with a bullet bill, severly injuring him. Luigi comes to aid Bob with medical supplies and tells SMG4 and Mario to go on ahead, and the two continue.
The scene then cuts to Yoko Littner preparing to take out SMG4 (who is knocked over by Mario spinning inadvertently) with her sniper rifle but then getting blown up by a grenade thrown by Saiko. After a brief moment, SMG4 runs into Mario again and notices him sitting on a beach chair, watching the battle with popcorn and calling it a "good firework show", much to SMG4's irritation. He then kicks Mario off the chair and drags him along just before the two bump into Tari who calls them to come over for assistance. SMG4 asks what's wrong and Fishy Boopkins explains that none of the soldiers can get past the point they're at because it's with too many lines barbed wire.
Mario gets an idea and runs towards the blockage. SMG4 starts to panic, but Mario tells him that there's nothing to worry about since "Mario's got 4 IQ". He then sees a landmine and falls on it, triggering it to explode shortly after; the force of the explosion throws Mario through the rows of barbed wire, blasting through it, allowing the passing of the forces.
Meanwhile, on the main warfront, Swagmaster, who is accompanied by Chris, pulls out a rocket launcher and shoots a bullet bill at a bunker, annihilating it, however in response snipers shoot down Chris. A devastated Swagmaster heads over to Chris and asks who's mom he's going to make fun of now. Chris tells him he's fine and that Swag must just kick their arses for him.
Swagmaster, filled with new determination, runs up to the snipers, dodging bullets, jumping over barbed wire, and climbing a hill as he does so before finally reaching the bunker and taking out the two snipers. Swag then enters the bunker and kills more anime characters, but one of the snipers who had survived nearly shoots him dead, but is then stabbed in the butt by Bob. The two then continue fighting.
The scene then cuts to Mario, SMG4, Tari, Boopkins, Saiko, Luigi and Chris in a trench where the former is patching up Chris who survived because the bullet missed his vitals while insisting that Chris needs to stay behind. The latter apologises for his failure but Tari assures him that it's not his fault, and that at least he fought bravely. SMG4 then shows everyone to the entrance to Francis' base while Mario exclaims he's ready to "Kill some bitches".
In the base, Meggy is being tortured in the The Ink Zuccer 2000, screaming in agony as her ink is getting extracted by the machine. Francis gloats about how it's working, but is then interrupted by one of his minions who informs him that the SMG4 gang have infiltrated the base, much to Francis' anger. Francis commands his minion to slow them down and goes to the Ink Zuccer's controls, shifting the Zuccer into maximum overdrive by speeding the machine's process up to 100%, putting Meggy through more pain. Axol and Desti plead Francis to stop as he might kill Meggy if he keeps going but Francis, wanting his plans to come to fruition, doesn't listen, claiming that Meggy will be fine. Suddenly, he hears chaos caused by the enemy taking out his goons and tells Mewtwo to watch the prisoners while he deals with the enemy his own way.
As it turns out, the SMG4 gang are finally on their way to Francis' base, running through the hallway and taking out each of Francis's henchmen, though SMG4 gets distracted by a False Hideo Kojima in a pink wig. Steve makes a cameo, seen cuddling with False Anime Creeper who, however, gets blown up by Saiko's rocket launcher (The screen cuts to black-and-white, a heartbroken Steve looks at the viewer and "Mad World" sung by Fishy Boopkins is heard). The SMG4 gang then come across Francis at the end of the hall, who reveals that he is the mastermind behind the kidnapping of all the inklings. Tari and the others realize that they made a horrible mistake of accusing Axol, and Francis boasts about how the latter isn't even half the otaku he is. Saiko angrily asks where Meggy is, but Francis mocks her by pretending to be afraid, only to be interrupted by Mario who threatens to beat him up if he doesn't tell where Meggy is. However, Francis, not wanting the heroes to ruin his plans, takes out a picture of Sephiroth, and jams Inkweaver into it, bringing False Sephiroth to life.
Meanwhile, near the Ink Zuccer, Axol, ashamed of creating Inkweaver, lost all confidence and will to continue helping the others and begins to blame himself for the situation unfolding around while Meggy continues to scream in agony. But after Desti motivates the axolotl to prove himself as the greatest manga artist, he comes up with an ingenious plan to free himself. He starts to taunt Mewtwo by telling it that he would rather choose Magikarp, making the Pokemon infuriating the Pokemon. Mewtwo then uses his powers and throws him away,landing near the machine's control panel, occasionally breaking his chains and giving him the opportunity to take off his straitjacket as well. After receiving another insult from Axol, an infuriated Mewtwo charges at Axol, who dodges, crashing into the control panel, which malfunctions and explodes, killing Mewtwo, terminating the ink extraction process, and Meggy's life is saved. Axol then proceeds to free Desti after getting a key from Mewtwo itself. Meggy thanks Axol for saving her, but then orders him and Desti to help Mario and the others after hearing of their struggle to fight False Sephiroth.
In the hallway near the now-disabled Ink Zuccer 2000, it's shown that the false Sephiroth has already killed many of the agents who accompanied the SMG4 cast to Anime Island. Mario attempts to gain an upper hand over the warrior, who effortlessly picks him, however Mario frees himself by quickly stretching his nose (like a penis), flinging the warrior away. At the same time, Saiko prepares to hit him with her hammer, but False Sephiroth ends up blocking her attack by launching Mario towards her. SMG4 then proceeds to bring out his computer to insult Sephiroth with a tweet that SMG4 made throwing shade at him, but starts crying after the roasting insult results in his computer getting destroyed by the swordsman, and the latter holds SMG4 against the wall. Fishy Boopkins attempts to intervene, only to get effortlessly thrown away. Having dealt with the others already, Sephiroth tries to attack Tari but ends up dealing minimal damage because of her cyborg arm. He immediately stops his attack upon hearing Francis and Axol fighting over Inkweaver. Taking advantage the distraction, Desti then proceeds to kick Francis, not only obtaining the pen (for now) but also causing the chameleon's glasses to come off. Still, due to his loyalty towards Francis, Sephiroth charges towards the Octoling and attacks her as the two end up in the room of the Ink Zuccer, followed by Francis once he realizes that he's being chased.
Near the disabled Ink Zuccer, Desti blocks Masamune with Axol's pen and jumps in an attempt to strike False Sephiroth from above, but gets blasted away as the pen lands back in the grasp of Francis. Saiko charges at Francis trying to get Inkweaver from him, but gets hit by False Sephiroth as well. Desti claims that she needs a distraction to defeat False Sephiroth, which causes Saiko to think of distracting the warrior with Tari's "secret weapon." The "weapon," which happened to be Archibald (Tari's rubber duck), confuses Francis and False Sephiroth, but allows Desti to grip the latter and throw him towards Axol. The manga artist then kicks him at Mario and SMG4 as they exchange their own series of blows, before False Sephiroth is finished off by a rock launched from the mouth of Fishy Boopkins with Luigi assisting via aiming (which triggers the Final Zoom effect from Super Smash Bros. Ultimate).
Upon witnessing their first win against Sephiroth, the SMG4 gang cheer and congratulate themselves on their victory, not realizing that Francis still has Axol's pen. Their celebration is cut short when Desti gets impaled through heart by another False Sephiroth's Masamune, mortally wounding her. Everyone watches in horror at what just happened with Meggy calling out to Desti in despair, while Francis reveals that he used the Inkweaver to summon another Sephiroth and laughs maniacally in the background as False Sephiroth unhinged his Masamune out of Desti's chest and she falls to her knees, through she tells her last words to ask Meggy to win the Splatfest for her, before she collapses to her death.
The screen cuts to the end credits without the SMG4 theme playing.
The events continued in next video.