When 27 Enters an Infinite-Flow World [Crossover]

Tsuna from a parallel world accidentally enters a ring at the age of five, then is mistakenly summoned to an infinite-flow world. Along with mission-takers from other worlds, he tackles all kinds of instances. From time to time, he also has to return to deal with the instances that appear in his original world. Here are the instances and characters appearing in them so far: First instance (orphanage): An older girl from the First Generation era, Oda Sakunosuke, little Tsuna Second instance (castle escape): Little Gokudera, little Tsuna [Best not to skip] Third instance (zombie world, research institute investigation): The older girl from the First Generation era, Oda Sakunosuke, Demon Slayer Rengoku, Celestial Spirit Mage Lucy Fourth instance (Japanese-style haunted house escape): Little Yamamoto, little Kyoko, little Ryohei, little Tsuna [This and the daily-life transition afterward contain important plot points, so it's best not to skip] Daily life and transition-training instance (a house tied to strange local legends): Young Gio, G, little Tsuna [formed from Gio's memories] Fifth instance (school): Boss Dazai, Jujutsu Kaisen Geto, little Tsuna Sixth instance (hospital): Little Hibari, little Kusakabe, little Haru, little Tsuna [This and the daily-life transition afterward contain important plot points, so it's best not to skip] Seventh instance (unnamed island, mermaid legend): The miko who once protected the Shikon Jewel, Oda Sakunosuke, Celestial Spirit Mage Lucy, Kuroko, the Shadow's Sixth Man, little Tsuna [Hidden character: a certain working older brother] Eighth instance (overlapping instances: research facility, train, amusement park, home, and more): R, a slightly younger Dino, little Mukuro, little Tsuna, little Enma, little Mami [Limited pairing: 270, 690; their souls are still little Tsuna and little Mukuro] [This and the daily-life transition afterward contain important plot points, so it's best not to skip] Ninth instance (two-track instance: prison, residence): Boss Dazai, a certain househusband, the older girl from the First Generation era, tennis player and wind mage Fuji [Limited pairing: 270; the soul is still little Tsuna] Tenth instance (city escape, rule-based instance): A younger X, S, little Chrome, little Tsuna [Limited character: little Mukuro] [This and the daily-life transition afterward contain important plot points, so it's best not to skip] Eleventh instance (infection with a criminal-gene virus): Boss Dazai, Tsuna Twelfth instance (city with red phone booths): Little Lambo, Tsuna [Major outside support: Hibari, Mukuro, and others] (important turning point) Thirteenth instance (bomb disposal in a park): Matsuda, Sakurahime of the Nurari Group, Fuji, Tsuna [Limited character: Hagiwara (very little screen time; he only makes an appearance, so don't get your hopes up)] Fourteenth instance (school swimming-pool mission): Yamamoto, Tsuna (important turning point) Fifteenth instance (women's village): The older girl from the First Generation era, Conan, Ran, Tsuna [First Storm] Sixteenth instance (Russian roulette): Gokudera, Kyoko, Tsuna [This and the daily-life transition afterward contain important plot points, so it's best not to skip] Seventeenth instance (the white lady of the William family): Izumi, Miss Shikimori, the miko who once protected the Shikon Jewel, the Forger family (Loid, Yor, Anya), Tsuna Eighteenth instance (sports day): Ryohei, Futa, Bianchi, Haru [Support: Gokudera, Yamamoto, Hibari, Dino, Mukuro, and others] Nineteenth instance (runway models): Celestial Spirit Mage Lucy, Fuji, a certain househusband, Oda Sakunosuke, Matsuda, Boss Dazai, Tsuna Twentieth instance (strategy game: entering the game console one by one, controlled by the others): Yamamoto, Gokudera, Tsuna [Lambo, Kyoko, Hibari, and others get caught up in it midway] Twenty-first instance (Chinese-style ghost bride): Detective Isshiki, Kamonohashi, Teacher Grizzly, Echizen, Tsuna [Mukuro is summoned for support] [Recommended, mainly for the teamwork between Mukuro and Tsuna] Twenty-second instance (filling in a blank manga): Hibari, Mukuro, Tsuna (mixer, amusement park, wedding chapel) [This and the daily-life transition afterward contain important plot points, so it's best not to skip] [You might miss out if you skip it (no pressure to read, just a recommendation)] Twenty-third instance (island, keeping the lighthouse): Lamplighter: Shaman Yoh Asakura, magical girl Homura, Tsuna; lighthouse keepers: Anna Koyama of the Fear Town, Madoka, Chrome [Important plot point] Twenty-fourth instance (shopping district, shopping list, repeat instance): 1. Haru 2. Basil, Squalo... [Lighthouse keeper: Chrome; phone booth: Mukuro; mutated space: Hibari, Gokudera, Yamamoto, Mukuro, Chrome, Xanxus, and others] (Five-star important plot point, best not to skip.) Twenty-fifth instance (police response mission): Hinata (accidentally enters after missing his original instance because he argued with Kageyama), Kageyama (accidentally enters after missing his original instance because he argued with Hinata), Matsuda (card summon: Furuya), Tsuna, super high school-level gamer Nanami Twenty-sixth instance (airplane): Uni, Basil, Tsuna Twenty-seventh instance (Byakuran arc, Hibari's space instance): Tsuna, everyone Twenty-eighth instance (mirror graveyard): Tsuna, Basil, Iruma, Azz, Rikuo, Yuki Onna Twenty-ninth instance (tower climb at the “TV station”): Tsuna, Uni, Byakuran (the three Sky guardians) [The instance itself may not be written very well, but the parts with the three Sky guardians might be pretty good, so give it a try] Thirtieth instance (delivery truck in another world and Simon Island instance in this world, happening simultaneously): Other world: Tsuna, Heine, Oda Sakunosuke. This world: the Guardians (they mostly handle the instance independently and don't get in Tsuna's way), Tsuna (focused mainly on Daemon) After that, Tsuna fights the outsiders. The main story's ending deals mostly with what happens after the outsiders are killed, and has a happy ending. Note: Many of the daily-life transition chapters in between contain important plot points, especially in the middle and later parts. Skipping them may mean missing clues and make the story hard to follow. *Matsuda appears as two different people. One is based on those two episodes (he doesn't know Furuya, but gets his card mixed up with the other Matsuda's and summons a Furuya who knows Matsuda). The other appears after the Police Academy arc; he hasn't appeared yet and has only been mentioned so far. The explanation is parallel worlds. Instances are divided into other-world instances and instances in this world. People Tsuna meets in other-world instances can also become his allies [cards can use the corresponding moves]. This is a plot-focused story about friendship and bonds. Since there are romantic interactions with Kyoko, it's tagged as romance. The ending has no pairing; the bonus stories feature Tsuna and Kyoko's romance as adults, so feel free to skip them if you aren't interested. Even when our meeting takes a different turn, we can still forge new bonds with our companions. Theme: Build a harmonious society and create a better world