Bleach's anime is returning later this year after the animated series was dropped in the mid-2010s or so. The manga series carried on, and the entire Thousand-Year Blood War arc unfolded in its pages, right up to the overall series' end. In preparation for this arc's upcoming adaptation, it's time to brush up on the Bleach anime's lore to remember who's who and what's what.
Some of Bleach's arcs are more consequential than others. Some of them set up vital characters, powers, relationships and settings, while others are more skippable, or are just the introduction to an even larger arc. Given the characters and settings involved in the upcoming anime arc, these four current anime arcs are vital.
The Substitute Soul Reaper Arc
The first arc of the Bleach anime is less coherent than the others since it lacks a single, major villain until the last second. Instead, this arc devotes itself to setting the stage for everything to come, and this is where many major players walk onto the stage and the combat system is established in its most basic form. One night, Rukia Kuchiki granted her Soul Reaper powers to Ichigo Kurosaki, allowing him to fight and defeat a monstrous Hollow and become a substitute Soul Reaper.
This reverse-isekai series, of sorts, gets off to a quirky and fun start, wherein Ichigo embarks on a "monster hunter" quest to vanquish Hollows and keep people safe; most of all, his twin sisters Yuzu and Karin. This arc also introduces Kisuke Urahara, a former Soul Reaper Captain who has mastered mad science and is ready to train any hero who needs help.
By the end of this "monster of the week" arc, the major players introduced include Ichigo and Isshin Kurosaki, Rukia and Byakuya Kuchiki, Renji Abarai, Uryu Ishida and Kisuke Urahara, all of whom will continue to serve important purposes in the sequel series.
The Soul Society Arc
The Soul Society arc may be considered the major arc of Bleach since it vastly expands upon the concept of Soul Reapers and the Soul Society, which is vital for the upcoming Thousand-Year Blood War arc. This is when Ichigo and his friends infiltrate the Soul Society and rescue Rukia from twisted justice, and they realize too late that all this was part of Sosuke Aizen's master plan.
In this arc, countless new Soul Reapers are introduced, along with their diverse zanpakuto. Uryu also faces the 'mad scientist' Captain Kurotsuchi, and Uryu reveals the true extent of his Quincy powers in that fight. Uryu had a close relationship with his Quincy grandfather, Soken Ishida, and Uryu nearly kills Captain Kurotsuchi out of revenge.
Elsewhere, Ichigo goes head to head with Byakuya Kuchiki to determine Rukia's fate, and by the end of their fateful duel, Byakuya is won over, becoming Ichigo's and Rukia's true ally. He will be on much better terms with Rukia from here on out, and this will be true in the upcoming anime arc, too.
The Arrancar Arc (First Half)
Most of the Arrancar arc's content focuses on the monstrous Arrancars who serve Sosuke Aizen, and Ichigo's struggle to master his Inner Hollow. Much of that is irrelevant to the upcoming season, but early in this arc, a few episodes flesh out Uryu and Ryuken's relationship, which does have some bearing on the upcoming season. Uryu has since lost his Quincy powers, and he convinces his father to train him and restore those powers in the heat of battle.
Ryuken complies, and Uryu is ready to use his powers for good; that is, to help Ichigo invade the world of Hueco Mundo and rescue his good friend Orihime Inoue. When Uryu departs, Ryuken and Isshin Kurosaki meet, and they are fully aware of each other's status as spiritual beings. Ryuken makes it clear that he has faith in his son's strength and abilities, and he's taking a hands-off approach to things. Ryuken is slowly regaining an interest in spiritual affairs, alongside Isshin.
The first half of this arc also introduces Grimmjow Jaegerjaques, a powerful panther Arrancar who will make a minor appearance in the Thousand-Year Blood War arc.
The Hueco Mundo Arc
The Hueco Mundo arc is a rough parallel to the Soul Society arc that came before since it involves Ichigo's brave team storming the enemy stronghold and fighting many boss battles to rescue a friend in need. This time, the desert world of Hueco Mundo is the setting, and here, Ichigo faces many enemies... and makes a few friends, too.
He runs into a toddler girl name Nel who is later revealed to be a former Espada, a powerful Arrancar. Nelliel had been ambushed, injured and reduced to a toddler state. In moments of distress, she can resume her adult form and use her powers to help Ichigo in combat, and she has two fracciones (minions) with her, too.
The world of Hueco Mundo will feature prominently in the Thousand-Year Blood War arc's early episodes, and Nelliel and her friends will appear as well. Viewers will definitely want to know why an unmasked Hollow like Nelliel is on such good terms with a Soul Reaper like Ichigo, and this arc shows how their friendship takes root. More memorably, perhaps, this arc is also the culmination of Ichigo and Grimmjow's rivalry.