When 27 Enters an Infinite-Flow World [Crossover]

Tsuna from a parallel world accidentally entered a ring at the age of five, then was mistakenly summoned to an infinite-flow world. There, he joins mission-takers from other worlds to deal with all kinds of instances. From time to time, he also has to return to deal with the various instances that appear in his original world.

Here are the instances and characters who appear 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, Kyojuro Rengoku from the Demon Slayer Corps, Celestial Spirit Mage Lucy

Fourth instance (Japanese haunted house escape): little Yamamoto, little Kyoko, little Ryohei, little Tsuna [this and the slice-of-life transition afterward are important plot points, so it is best not to skip them]

Slice of life and transition-training instance (a house in town with a strange legend): young Gio, G, little Tsuna [formed from Gio's memories]

Fifth instance (school): Boss Dazai, Suguru Geto from Jujutsu Kaisen, little Tsuna

Sixth instance (hospital): little Hibari, little Kusakabe, little Haru, little Tsuna [this and the slice-of-life transition afterward are important plot points, so it is best not to skip them]

Seventh instance (Nameless Island, mermaid legend): the shrine maiden who once guarded the Shikon Jewel, Oda Sakunosuke, Celestial Spirit Mage Lucy, Kuroko, the Phantom Sixth Man, little Tsuna [hidden character: a certain older brother who works part-time]

Eighth instance (overlapping instances: research institute, train, amusement park, family, and more): R, a slightly younger Dino, little Mukuro, little Tsuna, little Enma, little Mami [270 and 690 only: their souls are still little Tsuna and little Mukuro] [this and the slice-of-life transition afterward are important plot points, so it is best not to skip them]

Ninth instance (two storylines: prison and residence): Boss Dazai, a certain househusband, an older girl from the First Generation era, tennis player and wind mage Fuji [270 only: the soul is still little Tsuna]

Tenth instance (city escape, rules-based instance): a younger X and S, little Chrome, little Tsuna [little Mukuro only] [this and the slice-of-life transition afterward are important plot points, so it is best not to skip them]

Eleventh instance (crime-gene virus infection): Boss Dazai, Tsuna

Twelfth instance (city with red phone booths): little Lambo, Tsuna [major outside support: Hibari, Mukuro, and others] (major turning point)

Thirteenth instance (bomb disposal in a park): Matsuda, Sakura of the Nura Clan, Fuji, Tsuna [Hagiwara only: barely appears, so just be glad he shows up and don't expect much]

Fourteenth instance (school swimming pool mission): Yamamoto, Tsuna (major turning point)

Fifteenth instance (village of women): an older girl from the First Generation era, Conan, Ran, Tsuna [First Storm]

Sixteenth instance (Russian roulette): Gokudera, Kyoko, Tsuna [this and the slice-of-life transition afterward are important plot points, so it is best not to skip them]

Seventeenth instance (the white lady of the William family): Izumi, Miss Shikimori, the shrine maiden who once guarded the Shikon Jewel, the Forger family (Loid, Yor, Anya), Tsuna

Eighteenth instance (sports day): Ryohei, Fuuta, Bianchi, Haru [support: Gokudera, Yamamoto, Hibari, Dino, Mukuro, and others]

Nineteenth instance (fashion show models): Celestial Spirit Mage Lucy, Fuji, a certain househusband, Oda Sakunosuke, Matsuda, Boss Dazai, Tsuna

Twentieth instance (game walkthrough: taking turns entering an arcade game while the others control the player): Yamamoto, Gokudera, Tsuna [Lambo, Kyoko, Hibari, and others get dragged in along the way]

Twenty-first instance (Chinese-style ghost bride): Detective Isshiki, Kamonohashi, Mr. Grizzly, Echizen, Tsuna [Mukuro is summoned to help] [recommended, mainly for Mukuro and Tsuna teaming up]

Twenty-second instance (filling in the missing manga pages): Hibari, Mukuro, Tsuna (mixer, amusement park, wedding hall) [this and the slice-of-life transition afterward are important plot points, so it is best not to skip them] [you might miss out if you skip it; no pressure, just a recommendation]

Twenty-third instance (island, keeping the lighthouse lit): lighthouse keeper and spirit medium Asakura, magical girl Homura, Tsuna; lighthouse keepers: Anna of Fear Town, Madoka, Chrome [important plot point]

Twenty-fourth instance (shopping street, shopping list, repeatedly opening instance): 1. little Haru 2. Basil, Squalo... [lighthouse keeper: Chrome; phone booth: Mukuro; mutant space: Hibari, Gokudera, Yamamoto, Mukuro, Chrome, Xanxus, and others] (five-star important plot point, best not to skip)

Twenty-fifth instance (police dispatch mission): Hinata (gets lost here after missing the original instance because he argued with Kageyama), Kageyama (gets lost here after missing the original instance because he argued with Hinata), Matsuda (summoned by card: Furuya), Tsuna, Ultimate Gamer Nanami

Twenty-sixth instance (airplane): Uni, Basil, Tsuna

Twenty-seventh instance (Byakuran arc, Hibari's space instance): Tsuna, everyone

Twenty-eighth instance (mirror cemetery): Tsuna, Basil, Iruma, Azz, Rikuo, Yuki-Onna

Twenty-ninth instance (climbing the tower at a "TV station"): Tsuna, Uni, Byakuran (the Three Skies) [the instance itself may not be written very well, but the Three Skies parts might be pretty good, so give it a try]

Thirtieth instance (otherworld instance: delivery by truck + this world's instance: Simon Island, happening at the same time): Otherworld: Tsuna, Heine, Oda Sakunosuke. This world: the Guardians (they mostly handle the instance independently so as not to get in Tsuna's way), Tsuna (primarily focused on Daemon)

After that, Tsuna fights against outsiders. The final arc mainly covers what happens after the outsiders are taken out, and ends with a happy ending.

Note: Many of the slice-of-life transition chapters contain important plot points, especially in the middle and later sections. If you skip them, you may miss clues and have trouble understanding the story.

*Matsuda has two versions. One is an extension of those two episodes (he doesn't know Furuya, but gets the cards mixed up with the other Matsuda's and summons a Furuya who knows Matsuda). The other appears after the Police Academy arc, but hasn't shown up yet and has only been mentioned for now. That's what you get with parallel worlds.

Instances are divided into otherworld instances and instances in this world. People Tsuna meets in otherworld instances can also become his strength [cards let him use their signature moves].

Canon-focused, with the main emphasis on plot and bonds of friendship. There are romantic moments with Kyoko, so it is tagged as romance. The ending has no pairing; the bonus chapters are about Tsuna and Kyoko's romance as adults, and you can skip them if you're not interested.

Even if their meeting is different, they can still form new bonds with their companions.

Theme: Build a harmonious society and make a better fool