Re:Zero season 4

Following the Battle of Priestella, Julius' name was consumed by Roy Alphard, leaving him forgotten by everyone besides Subaru. To cure Julius, along with the Gluttony trio and Capella Emerada's other victims, Anastasia proposes seeking out the legendary Sage, Shaula. Subaru, Emilia, Beatrice, Anastasia, and Julius head back to Roswaal's mansion to prepare for the journey to the Pleiades Watchtower, where Shaula is said to reside. Along the way, Subaru also deduces that an artificial spirit Anastasia is contracted with is possessing her—a copy of Echidna in the form of a fox, whom Subaru nicknames "Foxidna". Foxidna explains that Anastasia's consciousness has gone dormant and the possession is gradually consuming the latter's lifeforce; thus, she seeks Shaula for a method to awaken her. After arriving at the mansion, Subaru reluctantly decides to bring the comatose Rem along on the trip, wanting to be there when she wakes up. He also recruits Meili to help traverse the mabeast-infested Auguria Dunes surrounding the Watchtower.

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Meanwhile, back in Priestella, Garfiel and Mimi visit the former's mother and bond with her new children, Fred and Rafiel, before parting ways.

With Ram joining them, Subaru's party sets off for the Auguria Dunes. After several days of traversing the desert, the group deduces that the area is under a huge spatial magic that prevents them from reaching the watchtower. Having been told by a local that birds have been spotted reaching the tower, Subaru has Ram use her clairvoyance on one, allowing them to find the way through. Unfortunately, they then find themselves surrounded by a pack of mabeasts, forcing them to flee until a flash of light from the tower snipes Subaru in the head, killing him. Respawning just before the chase, Subaru, Beatrice, and Patrasche take a different path towards the tower, only for the light to kill all three of them. Respawning again, Subaru successfully avoids the entire chase this time before having Ram use her clairvoyance to detect who is targeting him, allowing Emilia and Julius to deflect the first shot. Subaru and Beatrice erect an anti-magic field to neutralize more shots, but this interferes with the area's spatial magic, opening a rift that the group falls into. Meanwhile, at the watchtower, the girl who has been killing Subaru notes that she "found him".

Separated from the others and finding himself in an underground passage with Ram, Foxidna, and his land dragon, Patrasche, Subaru and his companions search for an exit. Going right after encountering a fork in the road, they encounter multiple closed doors that mysteriously open when Subaru interacts with them, until they reach one that refuses to open for some reason. Concurrently, the group grows strangely fatigued and anxious, leading to a fight between Subaru and Ram, resulting in Foxidna fatally stabbing the latter. However, Ram survives and bisects Foxidna, killing her. Patrasche then kills Ram before she can kill Subaru, only for the land dragon to turn on Subaru and kill him herself. Returning to before they turned right, Subaru deduces that the path is laden with madness-inducing miasma and convinces the others to go left this time. However, this leads them to cross paths with a powerful centaur-like mabeast. Fortunately, a girl from the watchtower appears and kills it, after which Subaru loses consciousness from fatigue.

Following a strange dream featuring the people whose witch factors he absorbed—Satalla, Petelgeuse, and Regulus—Subaru wakes up at the watchtower to find that his group has reunited with the others. He then meets the girl who saved him, who mistakes him for her "master", whose return she has been awaiting for 400 years, due to the miasma from his recent deaths. The girl reveals herself to be Shaula but clarifies that, contrary to common belief, she is merely the sage's disciple; the actual Sage was her master, a man named Flugel. Though Shaula cannot help them, the party concludes that they might obtain the knowledge they seek from the tower's library. However, they find that accessing it requires solving a riddle left by Flugel: "Who is the hero Shaula defeated"? While the others cannot make sense of it, Subaru deduces that the riddle refers to the star Shaula and concludes that the hero is Orion from Greek mythology. Having solved the riddle, the group is then teleported to the library.

Since Flugel's riddle used knowledge from Earth, Subaru concludes that the sage must have been transported to this world like himself. Exploring the library, he is shown Typhon's memories after picking up a book titled after the Witch of Pride: raised by an executioner, she developed a twisted morality that made her manifest the power to shatter anyone who considers themselves a "sinner". Deducing that these "Books of the Dead" contain the deceased's memories, the group searches for one with the answers they seek, but finds nothing. Concurrently, Subaru attempts to bond with Meili, prompting the latter to reveal that she was abandoned by her parents and raised by mabeasts. Foxidna also deduces that the tower has rules, and Shaula is contracted to kill those who violate them: 1. They cannot leave before completing all the exams; 2. They cannot violate the rules; 3. They cannot vandalize the library; 4. They cannot damage the tower. Concluding that completing the exams is their only option, the group takes the second exam on the next floor: a duel against an individual materialized by the tower, who calls himself a "Stick Swinger".

Julius accepts the Stick Swinger's challenge but gets utterly defeated despite Foxidna attempting to support him with magic. Emilia then takes the exam and successfully lands a hit on the Stick Swinger when he lets his guard down, after which he announces that she passed and grants her access to the top floor. Afterward, with the others denied access until they pass as well, the group moves to another floor to discuss strategy, during which Shaula reveals the Stick Swinger's identity: the Astrea family ancestor—the original sword saint, Reid Astrea. Meanwhile, Julius, who already deduced Reid's identity, slips away and retakes the exam only for the sword saint to repeatedly beat him, further plummeting his self-worth now that his name has been eaten. In the end, Subaru arrives and takes the injured Julius back with him. While Julius initially rejects Subaru's aid, he ultimately relents when the latter remains insistent about helping him.