Ollerus

Ollerus (オッレルス) is a mysterious fellow that once had the chance to become a Majin, but failed. Still, he is stated as one of the strongest characters in the series, and is currently being pursued by various magical organizations seeking his power and knowledge, but he has managed to elude all of them with ease.

Etymology
Ollerus is the romanized name of a legendary Norse God named Ullr. Kanzaki Kaori explicitly refers to Ollerus' namesake in the Norse Mythology SS, confirming the author's intentions.

Background
Not much is known about Ollerus' backstory. He has a history with the Saint Silvia, who was travelling the world to hone her Bonne Damme skills; how they met and the circumstances behind it are unclear, but it appears they've known each other for awhile. She's quite cruel to him on the surface and scolds him for being an "idiot to the core", but still cares for him deep down and feels an urge to protect him, and it is heavily implied she is in love with him. Silvia says Ollerus is a "damn dust-covered ruined noble", that he keeps getting wrapped up into all sorts of troubles ever since he failed to become a Majin, and that he sometimes cries late into the night when remembering the missed chance. There seems to be great antagonism between Ollerus and One-Eyed Othinus, the one who stole the title of Majin from him.

Personality
Ollerus is kind-hearted and sentimental person, to the point where he squandered the once in about 10,000 year chance to become a Majin in order to save a cat. He also destroyed a human trafficking organization and saved one-hundred children, when he did not need to, and did it knowing full well he would have to face Silvia's wrath over his overtly casual attitude. When one of the children he saved says she wants to repay him, Ollerus dismissed it by saying he didn't expect anyhing in return — a similar ideal Kamijou Touma holds. He also says that chaining up the human traffickers was meaningless because it was no different that what they did.

Thor points out a negative aspect of his methods, saying that Ollerus loses sight of his surroundings when he starts fighting, and does this with out concern for everything other then what he is trying to protect.

However, when the need arises, he shows a very serious attitude.

Appearance
Ollerus is a slim, short-haired blond man with green eyes, who wears a modest aquamarine thin shirt accompanied by a camel-coloured lambskin vest.

Toaru Majutsu no Index Light Novel Volume SS2
Ollerus first appears in Volume SS2, when he returns from the city of Milan in Italy. There, he destroyed a child trafficking organization and saved about one-hundred children. Since he had no idea what to do with them, he brings them to his and Silvia's apartment until they can find homes. There, Silvia berates him for making promises he can't keep and straddles him to the doghouse in their apartment's yard with rope, applying painful pressure to his crotch. Despite that, Silvia takes the children in. After dealing with that trouble, Silvia goes back to Ollerus, where they discuss that some of the one-hundred children were marked and shared certain characteristics — that of Gemstones. Ollerus disappears later that day.

We later see him infiltrating Academy City in order to put across a point to Academy City's Board of Directors and Aleister Crowley that if they misuse the Gemstones they took in and use them as lab rats in experiments, he will personally step in to stop them. Ollerus is confronted by nine of the ten Misaka Sisters remaining in the city, and he manages to defeat them all effortlessly. Then, on one of his patrols, the 7th Level 5 and greatest Gemstone Sogiita Gunha barges in on the scene and confronts Ollerus. Gunha, after seeing what Ollerus did to the Sisters, deems him a threat and attacks. Ollerus then uses the defensive spell called Hliðskjálf in an offensive way, which floors Gunha and knocks him down to the ground. Gunha, however, proceeds to get up without major injuries, and valiantly charges at Ollerus once again, only for the same result to occur. Ollerus says that Gunha doesn't understand his true powers, and that if he did, then he could defeat him. Gunha once again gets up and charges, though the battle cuts off there.

We later learn that Ollerus was victorious and Gunha is beaten into the ground. The difference between Gunha and Ollerus' powers was so large that though Gunha took Ollerus as a serious opponent and went all out, Ollerus was only toying with Gunha. Olerus returns to the apartment, where he is greeted by Silvia and some of the children he saved.

World War III Arc
Ollerus, having observed the Third World War from the sidelines, appeared at the end of Volume 22 with Silvia to rescue a dying Fiamma of the Right from the snow after his defeat at the hands of Aleister Crowley. Ollerus shows interest in Aleister's Age of Horus and says he can hide Fiamma if he tells him what he knows. Fiamma, asking who they are, is answered by Ollerus who introduces himself as the pathetic magician who had the position of Majin stolen from him by One-Eyed Othinus.

Baggage City Arc
Ollerus makes an appearance by confronting his nemesis, One-Eyed Othinus. The Majin and leader of GREMLIN, having just severed Kamijou Touma's right hand and crushed the Invisible Thing that came out as a result, only sneers at the sight of "The Failure". Ollerus declares he's not here to fight her, and suggests Othinus leaves with the unconscious Marian Slingeneyer as he has business with the Imagine Breaker. Both of them spar and discuss the principles of purity of Magic Gods amid sneers, until Ollerus reveals that he is not alone and has Fiamma of the Right on his side — his Holy Right empowered by the fact Touma's arm had been severed by her, enabling his world-saving powers to activate. Othinus seemingly agrees with Ollerus' previous suggestion, but on a whim decides to kill them. The battle ends in a draw. With Othinus gone, He and Fiamma assist Touma and watch as his crushed arm is restored. The three, under Touma's insistance, begin to use their talents to analyse Marian Slingeneyer's methods so they can restore her victims to normal, including Cendrillon.

Ollerus later changes Cendrillon back to normal, somehow giving her the ability to reconstruct her body.

Eve of the Festival
It is unknown how, but it can be presumed that Ollerus was the one who sent Touma back to Academy City, while he was unconscious. He, Fiamma of the Right, Silvia, Brunhild Eiktobel, and Leivinia Birdway, gather in Academy City to oppose Othinus and GREMLIN, who plans to capture Fräulein Kreutune, despite the fact that they could've intercepted them outside of Academy City, though chose to have the battlefield in Academy City in order to interfere with GREMLIN's teamwork, as Thor noted.

However, it was actually deliberate attempt by Ollerus to cover Fiamma of the Right's actions in a collection of very powerful people concentrated in a single cite, as well as to infiltrate GREMLIN. Some time in Academy City, Ollerus meets up with Thor and convinces him to be part of his plan, probably knowing that Thor has grown weary of GREMLIN's methods as of late. The specifics of the plan is unknown, though only Silvia may have know for sure, referring to Ollerus' actions as "preparing," when later questioned by Leivinia Birdway. Moreover, he might've charged Thor with the plan to liberate Fräulein Kreutune and to make her unusable for Othinus' use. He later used the oppurtunity to steal the real organs of Kakine Teitoku as an incentive for Othinus.

Ollerus appears before Kamijou Touma after he was tasked by Fukiyose Seiri to buy some food for them. He notes on how it took so long for Touma to sense him, noting that he lost a bet with Fiamma of the Right, and says that he wants to talk about the Imagine Breaker to him, but Touma ignores him much to his surprise. Ollerus later gets the opportunity to talk to Touma after he ran his errands. Here, Ollerus tells Touma of what a Majin is, GREMLIN and Othinus' goals, his and his Imagine Breaker's role in it, as well as his opinion regarding the nature of the Imagine Breaker.

It can be assumed that Ollerus later receives a report from Leivinia after her confrontation with Touma, detailing him on how GREMLIN has won him over.

During the Festival
After all battles have concluded, Ollerus successfully disguises himself as Thor, steals Kakine Teitoku's organs, and infiltrates GREMLIN. Ollerus disguised as Thor first appears in Tokyo Bay alongside Marian Slingeneyer and Mjölnir. Marian comments on what they will do now with the goals, seeing as Fräulein is beyond them now. Ollerus skillfully relates to her their plan of capturing Fräulein, and references on how there were unforseen elements that he couldn't overcome, and surely something Marian and Mjölnir would not likely overcome. Marian comments on how he should have since he has "Almighty" in his title as Thor, but Ollerus states that it only defined by humans and that he is not a magic god. Ollerus then shows a cooler, making Marian question it, to which Ollerus responds that it is an item that will better Othinus' mood after their failure. Afterwards, when Othinus comes and asks where Fräulein is, Ollerus tells her that they have failed. Othinus reiterates that she told them to get her, but Ollerus just tosses the cooler he had. He tells her that it is the original organs of Kakine Teitoku, a suitable substitute to the Fräulein, who is now useless to them. While Othinus remains silent, Marian asks if it would work, since they needed something that was not dyed in magic or science, to which Thor says that Teitoku is a symbol of creation and could create a doll for Othinus to use. Othinus reiterates her point, but Ollerus just tells her that if she wants to get Fräulein, she can do it herself, but adds that she is useless to them now. Othinus calls out to Marian before cutting Ollerus' arm out as punishment, telling her to reconnect it afterwards. However, Marian notices that Othinus' own arm is falling off after picking up the cooler, a side effect as a magic god. Having the final piece, Othinus tells Marian that they should begin making Gungnir. After Othinus leaves, Marian tries to approach Ollerus, but is shooed away by him, saying that he can do it himself, and that he doesn't want anyone to look at him in his state. He complains about Othinus' policies, but Marian says that he did well. Ollerus says that he didn't grant her wish, but then says that maybe he wants to cry not because of the pain or in a pathetic situation, but it's because Othinus spared his life. Marian says that he shouldn't worry as she too would have been scared if she was in the same position. With that, Marian snaps her fingers and Mjölnir follows her towards the rental ship.

Ollerus later simply reattaches his arm after being severed, and notes on how everything is going to plan, with Fiamma of the Right undetected, and him infiltrating GREMLIN. He later plans to find Othinus' base, where she will complete Gungnir, and begin his counterattack against her incognito.

Lance of Gungnir Arc
Othinus and the other core members of GREMLIN were in their base at Sargasso making the preparations to forge Gungnir. She then asks each of the members regarding the status of their assigned tasks and assigns Thor (Ollerus in disguise) to intercept the attackers once the lance enters production stage. He then asked if he could use Mjolnir to which Othinus replies that Mjolnir will assist Marian in the production of the lance and he should head out as Almighty Thor. He then thought on how he could obtain their location and inform the others about it while GREMLIN is busy with the lance.

Thor (Ollerus in disguise) called out to Marian and told her that since he can't use Mjolnir because she was assigned to support Marian, he'll head off as Almighty Thor. Thor (Ollerus in disguise) then explained that by heading off as Almighty Thor, he might hinder the production of the lance and asked the direction where they are going to draw power in to put together their temple so as not to overlap with their magical symbols, to which Marian handed her memo pad for him to check out. He then told Marian to keep Mokkerkalfe in mind since it may affect the ley lines to which Marian responded that she already knows that and she is more interested in its beating heart on the plate. He then parted with Marian and continued down the corridor where he spotted Bersi while thinking on how he will get the data out. He then decided to use the "heart on the plate" to control Mokkerkalfe remotely and borrow the line to send information to the Anglican Church.

He stood directly on the ocean via goat fur he had scattered across the ocean surface (it is a spell he constructed using the symbols of the goats that pulled Thor’s chariot) while listening to the rumbling caused by the battles happening around. He then considered if he would leave right away since everyone already knows where Sargasso is but then he heard a great roar from Mokkerkalfe and the approaching Academy City bombers. He then thought for a bit whether he would leave this to them but then he thought that there is no guarantee that they can do real damage to Othinus and that it would only cause them destruction so he decided to continue his recklessness a bit longer. He then commanded Mokkerkalfe to attack the bombers.

As Touma and the others approached GREMLIN's base, they were suddenly attacked by Mokkerkalfe, but Thor (Ollerus in disguise) killed Mokkerkalfe. Othinus suddenly appeared behind Thor (Ollerus in disguise) after he killed Mökkurkalfe and asked what is he doing. Thor (Ollerus in disguise) then said that it is about time and threatened Othinus regarding Marian. Othinus then threatened him to show his true self and he transformed back to his true self. She then questioned Ollerus motives of being there and someone's life or death won't stop her from carrying out her plan. Ollerus then remarked that he is glad that she didn't see through his plan and her infinite possibilities send her power to the negative direction. Othinus then responded in disappointment that there is no way she would add him to her ranks of Einherjar and she would totally obliterate him and Ollerus responded to her mockingly to which Othinus responded by creating tens of thousands or even hundreds of millions of strange explosions in the slight space between them. The battle between Ollerus and Othinus goes on then immediately, Ollerus rushed up to Othinus while disregarding the damage he is taking. He then jabbed his glowing palm at the center of Othinus chest to turn her into a fairy based on the idea that fairies were former pagan gods that were shrank down by Christianity without being aware of it. In that way, the magic god will be returned/dragged down to the territory of a human. But despite that, Othinus just laughed and told him that she deceived his senses and thanked him for giving her a means to finally defeat him. She then used the same move against Ollerus to turn him into a fairy. Ollerus then staggered and said that his second hope is still on track. Othinus was confused then suddenly she was stabbed by the same spell again, this time by Fiamma of the Right who seems to appear out of nowhere. Ollerus then told her that he no longer have an interest in becoming the magic god but he won't allow someone to misuse it. At that moment, it seems that it is all over for Othinus but she just laughed. She then told them that she doesn't care whether she lose, what's important to her is unifying her infinite possibilities. She only needed it to lean in one direction or the other. It did not matter whether she completed the lance and have 100% success or become a fairy and have 100% failure. Whether she win or lose, she will be a complete magic god. While saying all these things to Ollerus and Fiamma, Kamijou and the others approached GREMLIN's base. As they approached the end of Sargasso, Kamijou doubted if it is still part of the real world. He then sees Ollerus' body fall from the deck of a passenger ship.

Abilities
Ollerus wields the power of Nordic Throne (Odin's throne), related to Norse Mythology, and his power has been described as incomprehensible and inexplicable. He almost became a Majin or "Magic God" — one whose's magical powers has reached the level of divinity, and so can bend all natural laws — but didn't. It has been stated that he has used the knowledge from a lot of grimoires, though any possible ill effects he suffered is not mentioned. It was said by Silvia that he uses the theory of Hliðskjálf to purify his own life force so that it transforms into a special magical power. This just barely allows him to survive the process of taking in a grimoire's knowledge within him.

Ollerus has described himself as an impure example of a Majin, yet he can still wield that power. Unlike Othinus, who is a perfect and pure Magic God, Ollerus stopped his growth at the point where he should have become a Magic God. Because of that, his overall powers are weaker, but he doesn't have the 50/50 dilemma Othinus has to operate under.

Also, he can apparently reconnect his own body parts with ease, as demonstrated with his arm. He does not need to recite any spell nor to use any talisman or wonder drug. By an unknown method, he just presses his severed arm to his shoulder and it reconnects with a pale light.

Some of his abilities shown so far:
 * Hliðskjálf (北欧王座 (フリズスキャルヴ) ) — it is his power to change life energy and normal magical power into an unexplainable type of power. The power by its nature cannot be described, can't be explained, and can't be comprehended. Since the power cannot be comprehended, there is no possible defense to stop it according to Ollerus. The actual Hliðskjálf (which is the throne of Odin) doesn't have any offensive function, but by forcefully using Hliðskjálf as an offensive power makes it even more unexplainable. He uses Hliðskjálf due to the fact that his own mana is too special and can't be used with normal magical powers, even if he applied knowledge of various grimoires. In other words, he needs the unexplainable energy to be used up by Hliðskjálf to prevent a build-up of mana inside him and self-destructs.
 * Disguise — he disguised himself as Thor and it is efective to the point that no member of GREMLIN, nor even the magic god Othinus caught him in his disguise. Along with the disguise, apparently he can also use the magic of the real Thor (former member of GREMLIN) which includes the Lightning God Thor (connected to Mjolnir) or the Almighty Thor.
 * Turn into a fairy (妖精化 Yōsei-ka?) — the spell is specifically created to counter Othinus the Magic God and bring her down into a field where she can be defeated.

Design evolution
Ollerus' design remains static throughout the series. Haimura designed him as an opposite to Sogiita Gunha's intensity. He was given the same color as Index, due to her connection of being near a Majin, and had the print on his pants similar to the Jeans Slasher, as she is also related to Norse mythology, somewhat.

Quotes

 * (Ollerus reacting to Silvia's cold indifference to the children): "That’s too cruel!! There’s no way I can do that, you heartless woman!! Are you someone’s animal-hating mother!? Reaching out a hand when someone is in need is the basic law of the world!!"
 * (To a child he saved in SS2): "I am glad you adore me, but I didn’t really do anything. Chaining those human traffickers up and making them do manual labor is no different than what they did. That isn’t what I want."
 * (To Sogiita Gunha in SS2): "No, I really have no guts. But I have my reasons. Unlike you, I have a reason to fight."
 * (To Sogiita Gunha in SS2):"The most fearsome thing in this world is to be defeated by an attack using an unexplainable power coming from an incomprehensible place while you have no way of thinking up a counter measure. The attack is vague and you cannot assign conditions to it and you don’t even know if there is a direction you can go to avoid it or if you could even avoid it after getting tens of thousands of kilometers away. You now know how horrible that is firsthand."
 * (To Fiamma in Volume 22): "I am a pathetic magician who once should have become a Magic God, but had that position stolen by One-Eyed Othinus."
 * (To Othinus from NT volume 4): "No, I don’t think I can win. If I could, I would have killed you long ago. I will abstain from killing you as long as I have no means of doing so. That’s all there is to it."
 * (Regarding his power compared to Othinus from NT volume 4): "I am an impure example that stopped at the point where I ‘should have’ become a Magic God. In other words, I lose to you in overall power, but I am freed from that 50/50 dilemma. After all, I am imperfect. Unlike your perfect balance, my odds of victory have a deviation."
 * (To Othinus from NT volume 8): “So instead of trying to bring mankind higher, I will drag you down. I will tear off your wings, strike you from the air, and throw you to the throngs of people who can only crawl along the ground. …This is the end. Even if humans cannot kill a god, we can manage against a fairy.”