Yuuki Kagurazaka

"“Of course I won’t. I am definitely going to rule the world. And then everyone will live happily ever after!”"

- Yuuki

Yuuki Kagurazaka (神楽坂優樹) is a Japanese Otherworlder summoned into this world and also used to be the Grandmaster of the Free Guild. He has some connection to Shizue and thus to Rimuru. Currently, he's the Commander of the Eastern Empire's Mixed Corps, one of the four heads of the Imperial military.

Appearance
He's considered fairly handsome, with black hair and black eyes. He looks as young as a middle schooler, despite his real age being in the twenties.

Personality
Yuuki is a kind, good-natured, and hardworking person. Always bright and optimistic, Yuuki is an ideal for many adventurers for his many good deeds and is also a master in manipulating others and will do so without hesitation to achieve his goal of a just world that treats everybody fairly.

Background
A natural born genius, Yuuki was satisfied with his life on earth. He had loving parents and plenty of friends. But after an overworked truck driver fell asleep at the wheel and crashed into his parents car killing them both, he fell into despair. When the courts ruled the driver innocent, Yuuki discovered the unreasonableness and flaws of society. He initially wanted to take revenge and tear it all down but couldn't bring himself to inconvenience so many innocent people in the process. Instead, he realized that he would have to change society one step at a time by becoming a politician and gaining like minded friends and allies who would help him achieve a more fair society. But before he could even finalize his plans he was summoned to the otherworld.

Kazaream, a former demon lord on the verge of death due to his defeat at the hands of Leon Cromwell, had summoned Yuuki whose material body and spiritual body was compatible with their astral body and attempted to, with the last of their strength, lay a curse on Yuuki that would kill his mind instantly and allow them to reincarnate into his body. However, Yuuki being a genius who already understood how the world worked during the trip between worlds, had awakened his Unique Skill "Creator" and used it to make his special "Anti-Skill", letting him resist the curse. Yuuki, taking pity on Kazaream, allowed them to inhabit his body and promised to find a body for them to reincarnate into saving their life.

After letting Kazaream inhabit his body, at some point he wound up under the tutelage and guidance of Shizue Izawa alongside fellow student Hinata Sakaguchi, who were fellow countryman, where he learned about the world's language and society. Alongside his teacher, Yuuki used his knowledge of a more modern world to rework the society of adventurers into the internationally accepted Free Guild, which he was then appointed Grandmaster of. Under his leadership, monster related deaths decreased dramatically and a new system of ranking monsters based on their amount of magicules was established. These changes allowed for trade to blossom and the population to boom in areas that were previously poor and decrepit, improving the lives of many.

At some point Yuuki encountered Mariabell Rosso who was secretly manipulating society and the economy from behind the scenes via the Council of the West, which she had complete control over. Mariabell stood as an absolute roadblock in Yuuki's goal of a fair and just society and blocked his plans off at every turn, much to Yuuki and Kazareams annoyance. At sometime Yuuki met Damrada and crushed the dark organization in the east known as "Echidna", reforming it into the underground organization Cerberus, he appointed Vega, Misha, and Damrada as its commanders. Eventually, an opportunity to strike back at Mariabell came when she attempted to dominate him with her Unique skill, Greed. Yuuki managed to resist her domination due to his "desire" being stronger than hers and used his position to secretly influence Mariabell's mind and actions in return.

One day he met Rimuru Tempest, a slime who had murdered his teacher Shizu and taken her appearance. Rimuru, to his surprise, also turned out to be a fellow Japanese and after explaining the circumstances of Shizu's death, which Yuuki begrudgingly accepts, the two get along well and Rimuru's gifts of recreated manga and stories of what happened since his summoning in Japan greatly pleased him. Yuuki accepted the last wish of his teacher and allowed Rimuru to take her place and teach the students of Class S, summoned children who Yuuki had taken into his care that were too young to handle their own power and doomed to eventually perish.

While Rimuru was acting as a teacher, Yuuki sent Kazaream's subordinate, Laplace, in order to gain information on the Western Holy Church's headquarters in Ruberios, believing it to be a corrupt organization that stood in the way of his ideals. At the same time he had Kazaream's demon lord successor, Clayman, attempt to control demon lord Milim Nava and gather souls in order for Clayman to awaken as a True Demon Lord. However, learning that the initial plan of awakening Clayman via the destruction of Eurazania had failed, he set his sights on accelerating the start of a war between Tempest and Falmuth, which had gained too much power and influence via the mass summoning of otherworlders, ideally so he can gain souls for Clayman's awakening at the same time. However things didn't go according to plan. Rimuru who he sent Hinata Sakaguchi to kill on his return trip to Tempest, had somehow survived and the entire Falmuth army died at his hands. Even their bodies and souls were nowhere to be found, leaving Yuuki slightly anxious that Rimuru had summoned some kind of monster offering them as sacrifice. Falmuth being weakened by their defeat was an acceptable result, but Rimuru who survived and was much stronger than expected would undoubtedly become suspicious of Yuuki and make it harder for him to move, making the entire ordeal a massive pitfall that Yuuki regrets falling into deeply. Meanwhile Laplace, who had returned from his infiltration, reported the the pope was in fact a vampire, and with the help of Kazaream who had now inhabited a homunculus and taken on the name Kagali, they were able to confirm his identity, Demon Lord Valentin. Nevertheless even without Hinata, Yuuki still had a means of dealing with Rimuru before things got out of hand. He had Clayman use Frey and Millim to start a Demon Lord's Banquet in order to have the rest of the demon lords unite to take on Rimuru, hopefully destroying him before he became a problem. But things seem never go as planned when it comes to a certain slime, Rimuru had somehow managed to attend the banquet himself and turn the demon lords against Clayman, gaining their support to take his place before killing Clayman himself. With Clayman dead, it left both him and the rest of the Clown Troupe to mourn his loss in defeat.

After things settle down, Yuuki accepts Rimuru's invitation to the Tempest Opening Festival reuniting with both Hinata and Rimuru, as well as having a good time enjoying the nostalgic foods and music. Mariabell as well as several of her collaborators also attended the festival and he took great joy in seeing them try and fail to trifle with Rimuru. While there he also got a good idea of Tempest's military might which was so outrageous that he instantly cut any thoughts of making them enemies from his mind and leaving only ideas of further cooperating in the future.

Cutting his loses with Rimuru and the Church mostly short, Yuuki decides to focus all his efforts into overthrowing the Rosso clan and their influence in the Western Council. Mariabell, who saw Rimuru as an enemy to her goals of economic domination, planned to attack him during his exploration of the ruins of Amalita, which was Clayman's former domain that was once the capital city of Kazaream's country of dark elves. However, due to Yuuki's deception and mental manipulation, her plans had become sloppy and full of openings and Yuuki took the opportunity to personally kill her off. Stopping her tyrannical rule from ever happening and gaining her unique skill "Greed", as well as blaming all of his shady actions on Mariabell in the process.

Reflecting on the conflict with Mariabell, he was able to figure out that the "God" of Luminism was actually Luminous Valentine, a demon lord. Negotiating with Mariabell's great-grandfather and head of the Rosso clan, Granbell Rosso, they devised a plan to take down Luminism by unleashing the incarnation of evil itself, Chronoa, in Ruberios while demon lord Luminous was distracted with demon lord Rimuru's performance. The plan ended up backfiring horribly for Yuuki, who was tricked by Granbell, and he had to abandon all his operations in the west and flee east due to being completely exposed to Rimuru.

While fleeing Ruberios and planning to regroup with Kagali so they could move all their operations to the Eastern Empire, Yuuki was confronted head on by the "Lord of Darkness" and original demon lord, Guy Crimson, who proceeded to beat Yuuki into the ground. Even unleashing all his power of "Anti-Skill" and "Creator" evolving him from a human to a fully spiritual saint, as well as his intrinsic psychic abilities, it wasn't enough to leave so much as a scratch on Guy's body. Yuuki, realizing Guy's intentions, manages to negotiate for his and his friends survival in exchange for them doing their best to help destroy the Eastern Empire from the inside. After the fact, frustrated by his own lack of power and inability to protect his friends, Yuuki reached inside himself and managed to awaken his Unique skill "Greed" into Ultimate Skill "Greedy King" Mammon.

After fleeing the west, Yuuki took asylum in the Eastern Empire. Joining it's Mixed Corps, he managed to beat all of his superiors and in just a matter of months, rose to the rank of corps commander, one of the four highest positions within the Military.

Kagali
Yuuki's Summoner and partner who acts as his secretary and helps shape his plans. They shared a body for 10 years before Yuuki managed to get his hands on a Sarion homunculus.

Moderate Harlequin Alliance
Yuuki's precious friends who he has absolute trust in.

Clayman
Yuuki heavily regrets not being able to save Clayman and saw him as an ally whom was extremely beneficial to his plans. Yuuki mourns his death with the rest of the clown troupe.

Shizue Izawa
Yuuki thinks highly of his teacher Shizu who was almost like a mother to him and was initially angry at the fact that Rimuru murdered her. Yuuki was the one who got her up to speed on the current state of affairs in Japan. Shizu's knowledge of the catchphrase "I'm not a bad slime, Slurp!" came from him.

Hinata Sakaguchi
Yuuki would sometimes meet with Hinata and exchange intelligence with each other.[1]

Students of Class S (Kenya, Ryota, Alice, Chloe, and Gale)
Yuuki pities the otherworlder students of Class S and wishes he could help them in any way.

Rimuru Tempest
Yuuki is grateful to Rimuru for letting him read manga; saving the kids of class S; and bringing peace to the Jura Forest. Yuuki claims that he would back Rimuru if there was a conflict against the Church. As the series progresses, Yuuki slowly addresses Rimuru as a very serious threat to his plans.[2]

Guy Crimson
Yuuki acknowledges his strength but his desire to defeat him hasn't waned one bit. Loosely operating under Guy as his pawn to crush the Eastern Empire.

Greed (evolved to Mammon): The ability to dominate anyone whose desire is less then the desire of the owner.
Creator: A special energy that can change form into whatever Yuuki requires for the situation, limited only by his imagination and energy. An extremely versatile ability that created Anti-Skill and evolved Yuuki from a regular human into a Saint in a matter of seconds. It can also analyze other people's Unique Skills, but only if they're being used in his presence.


 * Anti-Skill: Invalidates skills, abilities or magic. This however, does not work on secondary effects, such as burn of oxygen due to fire magic. It also cannot counteract two or more properties when it comes to magic and skill fusion.

Ultimate Skills:
"Greedy King" Mammon

Trivia

 * Yuuki is one of the characters who had been changed the most between the Web Novel and the Light Novel. His entire character has been reworked and his motivations are completely different, to the point that his actual "role in the story" might end up a completely different one in the Light Novel compared to the Web Novel.
 * If Yuuki converts all his energy into magicules, he could rival the likes of Luminous and Leon.