Al

Aldebaran (アルデバラン), commonly known as Al (アル), is a member of the Priscilla Camp and plays the role of Priscilla Barielle's knight. Though only having supporting roles in Arc 3 and Arc 5, he is one of the main supporting characters of Arc 7.

Introduced in Arc 3 as Priscilla's constantly abused knight, it is quickly revealed that there might be more to him, following the revelation that, like Subaru, Al was summoned to the new world from Japan roughly 18 years ago. In Arc 5, his air of mystery only increases as he is revealed to have an ability similar to Subaru's Return by Death and is rather familiar with the Witch Cult and its members.

Currently, Al is accompanying Subaru, Vincent Abellux, Medium O'Connell, Taritta and Louis Arneb to the Demon City of Chaosflame, in order to try and prevent 7th ranking Divine General Yoruna Mishigure from joining their enemy's camp and act against Vincent.

Appearance
Aldebaran stands at five feet and eight inches tall, making him the same height as Natsuki Subaru. When meeting Subaru for the first time, Al was pushing to his late thirties to early forties. Al's frame is stocky and his body is covered in thick bulging muscles that give him an imposing impression. After an unfortunate incident in the Empire of Vollachia, Al lost his left forearm. Instead of resorting to a prosthetic limb, Al had the stub where his forearm used to be covered in bandages. There are various other scars scattered across his body, including a pair of claw-like marks on his right forearm and a vast assortment of scars on his face that left him disfigured. His overall shabby look, including his clothes and unshaven legs, make him look like a bandit or some other kind of lowlife. It could be said that his appearance is the polar opposite of his mistress, Priscilla Barielle.

Every piece of clothing Al wears gives a slightly different impression. His ensemble consists of a pair of green split-toe sandals with yellow buckles, sand-colored linen trousers, a bandage around his right wrist that matched the one that goes around his missing limb, bandages of the same assortment that are rapped around his feet like socks, an open green linen vest with yellow lining and a hem of white fur, and a shabby yellow mantle that reaches down to his hips. Additionally, he wears a brown belt with a golden buckle that has a collection of green pouches attached to it with his Blue Dragon Sword usually sheathed nearby. His most defining physical quality is the pitch-black helmet he uses to conceal his scarred face. The helmet in question, in contrast to the rest of his clothing, is very refined and features a plume of neat red hair as a crest.

Under his helmet, Al has long black hair wrapped in a ponytail, black eyes, and a stubble beard. He wears the same outfit as before when regressed to his younger self, but instead of his helmet, he uses wrapping to cover most of his face. From the visible parts of his eyes, he appears to have sanpaku, with small irises that make the whites of his eyes stand out. Additionally, his black hair is partially dyed with purple strands and red at the tips.

Personality
Al has a frivolous and goofy personality, and having spent more than ten years in a different world, he was easily able to get along with Subaru. Despite being Priscilla's knight, he doesn't really recognize himself as one, seeing himself as her caretaker, while Priscilla herself sees him as a handyman and a jester to entertain her. He has no qualms about their relationship. He also brags that the only way he can fight is by outwitting people and catching them by surprise.

Although very skilled at fighting due to the time spent in Vollachia, Al does not like to make enemies, as he considers that taking care of them when a problem occurs requires a lot of work, though Priscilla doesn't seem to care about this.

Outwardly, Al is an overly friendly man who speaks pleasantly to most people he converses with. He isn't quick to anger, as he usually brushes off the insults of Priscilla and Subaru without placing any kind of stock in them. Because of his light-hearted tone and friendly disposition, Al is a man who is easy to get along with even when taking his eccentric behaviour into consideration. However, his attitude also portrays him as a childish man who needed to shape up and act his age. Despite happily wearing strange clothing that labelled Al as a suspicious character upon first sight, the man from another world does care somewhat about his appearance, as he demonstrated insecurity regarding his disfigured face several times. He adores the helmet that he wore on his head, as he felt that he wouldn't be able to have face-to-face conversations without it.

Despite his easy going attitude, Al is deeply affected by having a form of amnesia. Until he met Subaru he sometimes had episodes where he would think of himself as losing the plot due to the memories he had from Earth. It's unknown how Al's amnesia came to be.

History
Al was summoned to the different world roughly 18 years earlier. One time, he visited the Gladiator Island Ginunhive in the Vollachian Empire to learn how to fight and received a sword, however, while staying there, he lost his left arm in an unknown battle. He spent nearly a decade there as a Sword Slave fighting in the Colosseum until one day one of the gaolers let him escape because they could see that his eyes were full of purpose, unlike the other gladiators. To help him fund his journey out of Vollachia the gaoler gifted him his trademark black helmet which was made in the image of the helmet worn by one of the Colosseum's heroes.

Sometime later, Al joined Priscilla's knight tournament, an event with around fifty people participating, but failed to win. However Priscilla decided to choose him as her knight instead of the top 4 contestants.

Al is apparently acquainted with a Sin Archbishop, as he told Capella that she was "considerably different from the Sin he knew". He also is in some way acquainted with the Witch Cult and the Witches of Sin, as he knew that Typhon died in Priestella, where her remains resided, and he also knew about Gluttony's authority.

In The Crimson Countess and the Gladiator, Al states that silver hair brings him bad memories about how a "trash, stupid useless person he is" due to how he failed to be of any use and to protect the one he cherishes the most. He was saved on the verge of death by Arakiya, who was then later saved from The Gladiator Empress by Al in return. He stated how he changed Arakiya's fate by saving her, and then reflected that the world may receive a big change if she were to get children in the future. As he thought this could be one of the marks he had left on the world, he then mentioned that he would get shouted by his "sensei" if he were to say it out loud.

Abilities
Unknown Authority: Al has been shown to possess a yet-unnamed and unexplained ability which he himself calls an Authority. In order to activate it, Al must meet a requirement which currently remains unknown. Once activated, space-time warps around Al, creating a "territory" of sorts within which, the Authority is active and can take effect. Whenever Al or the target dies within it, while the territory is active, time within the territory will reset back to a past point in time. Al also described it as a metaphorical coin flip, which decides the "role" (for lack of a better term) Al plays in his territory. Al also cannot seem to control which role he receives.
 * If he is the "victim", he will be able to remember previous loops in his territory while his opponent won't. If Al is the "victim", this ability functions as something eerily similar to Return by Death, with the two notable differences being that he has the advantage of him being able to choose a checkpoint and the disadvantage of it not being automatic. There doesn't seem to be a limit to how many times he can die like this, as he died to Priscilla a thousand times trying to convince her not to go to the Empire of Vollachia.
 * If, on the other hand, Al is the "subjugator", his opponent will remember the previous loops while he won't. His opponent is then trapped in a never-ending loop of trying to kill Al, seemingly unable to escape until they lose their minds. Al will be unaware of his deaths and can just deactivate the ability almost as soon as he casts it, as, from his perspective, his opponent went instantly insane. This was demonstrated in the The Day I Gave Up On Being A Following Star side story.
 * It should be noted that if the territory is broken (how this can be done is unclear) or if Al leaves or deactivates it, he becomes vulnerable once again as shown in his fight against Capella Emerada Lugnica in Arc 5.

Magic User (魔法使い Maho Tsukai): Al is able to use Earth Magic.
 * Dona (ドーナ): Al can summon one earth wall, which is used as a defensive spell.
 * El Dona (エル・ドーナ): Al conjures a swarm of earth mana and pinpoints it at the body of a target, usually channeled through a medium, which then the effected area bursts into spikes from the inside out and expands outward. This magic was cut from the Light Novel.

Equipment: Al owns a weapon called the Blue Dragon Sword and wears a black helmet which he received when he was at the Gladiator Island Ginunhive. Priscilla asked him one time if the helmet was a replica of a helmet related to the Gladiator King and he confirmed it.

Trivia

 * According to the author, Al is involved with one of the three mysteries of Re:Zero, and revealing his circumstances would answer it.
 * Al's full name is Aldebaran, the brightest star in the Taurus constellation which means "The Follower". However, he does not like being referred to by his full name.
 * The reason why Al denies being a knight is because he absolutely hates knights.
 * On April 12, 2020, Al's voice actor Keiji Fujiwara passed away due to cancer.
 * Al stated he is fond of silver haired girls, just like Subaru.