To contain the violence, the government of Neo-Tokyo implements the "XB Law", stating that all future conflicts between Tribes will be settled through games of "Extreme Baseball", overseen by robotic umpires.

The games are similar to baseball except there are fewer restrictions on equipment, the "field" can be as big as an entire ward, and the only ways to get an Out require striking out the batter or tagging out a baserunner while holding the ball.

A wild, stubborn biker gang of a Tribe based out of the special ward of Adachi who use an old enclosed shopping arcade as their home field.

Their leader, Fucho Sonoda, is constantly under assault by other tribe members that threaten to take his head, and he violently crushes them to maintain his position.

Based out of the Setagaya special ward, this Tribe is led by Eiji Todoroki, who thinks that he can buy anything with enough money, from bikini-clad women to victories in XB.

Various streamers have made cameo appearances in the series' English dub, including CDawgVA, Cr1TiKaL, Disguised Toast, Sykkuno, Technoblade, Valkyrae, and Yong Yea.

Nicholas Dupree called it a "light and breezy premiere" that told its solid and quirky baseball story with striking character designs and "high-octane spectacle" but felt it was held back by its "clearly modest production".

Richard Eisenbeis was also critical of the animation not showcasing the baseball scenes and character designs to its fullest, but concluded that: "[T]his first episode is 100% style over substance and it's a blast to watch.

Conversely, Rebecca Silverman criticized the over-the-top premise for lacking a "touch of logic" to make it grounded and the constant bullying of Haru to get involved in the game.

[25] Fellow ANN reviewer Monique Thomas chose Tribe Nine as her pick for the Worst Anime of Winter 2022, feeling disappointed by the "extremely limited" production making the art style and baseball scenes "stiff and boring", and the overall cast and XB world coming across as "barebones", concluding that: "It's not the complete worst, if anything I'd overall describe it as "mid," but compared to everything else I was watching, Tribe Nine struck out.