Yuuki Kagurazaka

"“Isn't that obvious? Let's make sure we rule this world. And then we will all live happily ever after!”"

- Yuuki

Yuuki Kagurazaka (神楽坂優樹) is a Japanese Otherworlder summoned into this world and the one who made the Free Guild into what it is today. He serves the role of a deuteragonist for most of the series.

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

Personality
Yuuki is, at his core, a compassionate and caring person who wants to do everything in his power to help other people. His ideology is that of 'Freedom' and he hates people and things that restrict the freedom of others in any way. After the death of his parents, he vowed to change the unfair world that caused him and others suffering unnecessarily. He has a naive and childish goal of 'World Peace', wanting to create a world where he and his friends can laugh and have as much fun as they want.

His methodology is to surround himself with like-minded people and friends so that they can all work together to make the world a better place, knowing well that it's a path no person could walk alone. He is always willing to reach out a hand to those who are in need, offering them kindness and understanding no matter who they are or what they've done in the past. He prefers to do things through political measures and negotiation, only resorting to violence as an absolute last resort when all other options simply aren't feasible. His immense drive to never give up, to protect his friends, to make the world better, in combination with his genius-level capabilities give him the absolute confidence of victory, something that makes him shine like a star and makes others think that his naive ideals can truly be made into reality if it's him at the wheel.

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 Central World.

Kagali, a former demon lord on the verge of death due to their 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 spirit 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 constitution, Anti-Skill, letting him resist the curse. Yuuki, taking pity on Kagali, allowed them to inhabit his body and promised to find a body for them to reincarnate into, saving her life and giving her hope.

After letting Kagali inhabit his body, at some point he wound up under the tutelage and guidance of Shizu alongside fellow student Hinata Sakaguchi, who were both Japanese countrymen. There 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 and other factors 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 Kagali's annoyance. At sometime, Yuuki met Damrada and crushed the dark organization in the east known as "Echidna," reforming it into the underground organization Cerberus, a place where he and his friends could be at last free from Mariabell's eyes and ears. He appointed Vega, Misha, and Damrada as its leaders. 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.

Trivia

 * Yuuki is one of the characters who has 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" is 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.
 * Yuuki's English Voice Actor, Clifford Chapin, also voices Gobzo.
 * Although he is believed to be the series' main antagonist, his motives are really to create a peaceful world, but it would require causing chaos to complete this goal.