Bleach

Bleach is a classic shonen anime (2004–2012, 366 episodes) based on Tite Kubo's manga, with a revival sequel series called Bleach: Thousand-Year Blood War starting in 2022 that adapts the final arc.

Quick synopsis:

Ichigo Kurosaki is a tough, orange-haired high school student who can see ghosts — something he's dealt with his whole life. One night, his family is attacked by a monstrous Hollow (a corrupted, soul-devouring spirit), and he's saved by Rukia Kuchiki, a Soul Reaper (Shinigami) whose job is to send souls to the afterlife and purify Hollows.

During the fight, Rukia is badly injured and — to save Ichigo and his family — transfers her Soul Reaper powers to him. This turns Ichigo into a Substitute Soul Reaper, giving him massive spiritual power (and a giant sword called a Zanpakutō).

The story follows Ichigo as he balances high school life, protecting his friends and town from Hollows, and eventually getting pulled into the much larger world of the Soul Society (the afterlife realm where Soul Reapers live and operate). There are epic battles, betrayals, powerful enemies (like the Arrancar, Visored, and later the Quincy), and Ichigo constantly unlocking new levels of power while uncovering secrets about his own origins and abilities.

It's action-packed with awesome sword fights, Bankai releases, over-the-top character designs, and a mix of humor, drama, and escalating stakes across its arcs.

If you're just starting, the first arc (Agent of the Shinigami/Substitute Soul Reaper) sets everything up perfectly in about 20 episodes.