Manta walks into a shaman's life and never leaves, that's the whole show, and it works because Yoh's fundamentally decent in a way most shounen leads aren't. The middle section breathes, letting you actually know these characters before the tournament starts grinding toward its finish. It hits the manga completely, which means you get the whole story, even if the pacing feels like it's running three different speeds to get there.
Manta is a normal middle-schooler until he stumbles upon Yoh Asakura communing with spirits in the woods. Yoh can see ghosts, talk to them, and let them possess his body to channel their supernatural strength. This isn't a hobby: it's his destiny. A tournament called the Shaman Fight happens once every five centuries, and shamans from across the globe compete to become the Shaman King, someone who communes directly with a powerful spirit force. Yoh has entered the competition, backed by his fierce fiancée Anna and a loyal samurai ghost named Amidamaru. What starts as an action-packed tournament becomes something darker when Yoh learns about Hao, a ruthless shaman with the same goal. Unlike Yoh, Hao plans to reshape the entire world to eliminate non-shamans. As Yoh battles through increasingly dangerous opponents, he must balance winning the tournament with stopping Hao's apocalyptic vision. Manta finds himself pulled into this supernatural underworld, watching his friend grow stronger while the stakes climb higher than anyone expected.