The World's Finest Assassin Gets Reincarnated in Another World as an Aristocrat

Pretty young girls have been captured and are being sold off at an illegal auction. Marquess Collide is engaging in human trafficking, and all her buyers are evil nobles as well. By royal order, Lugh the assassin, Dia the mage, his assistant Tarte, and Maha the intelligence expert begin their investigation of Marquess Collide. However, Dia is captured by Marquess Collide and put up for auction--

Lughs magic teacher is a pretty girl named Dia. Being a few years older than Lugh, Dia treats him like a younger brother and sneaks into his bed every night in order to sleep next to him. Because he needs her to teach him magic, Lugh cant complain, but gradually he and Dia grow closer--

Officially a family of renowned doctors and assassins behind the scenes, the house of Tuatha Dé is the right hand of the kingdom. Trusted to become his fathers heir, Lugh assists his father with his mission. However, there are those who are displeased by Lughs success. Lugh defends his status in a challenge against them--

With the success of his cosmetics brand Orna, by acquiring financial power and the Balor Trading Companys information network, Lugh has gained even greater strength as an assassin. However, since being reincarnated in this world, Lugh still has not completed a proper assassination. Then, Lughs father Cian tells him that he doesnt have to become an assassin--

In front of Lugh and Talt whove just finished a magical training camp in a deserted island, Maha appeared with information. Its about Swoigel kingdom being engulfed in a civil war. Lugh heads toward Dia, but Viecone territory seemed peaceful as always. Lugh was still worried, but Dia ignored him and suggested to go on a date instead.

Lugh and Dias father come up with a plan to fake Dias death and safely sneak her into to the Tuatha Dé region. Unfortunately, the arrival of Setanta MacNess thwarts the plan before they can enact it. As Setanta is the wielder of Gae Bolg, Lugh knows that he will not survive a direct confrontation with him, so he fires a magnetically propelled tungsten projectile into the atmosphere and stalls Setanta long enough for it to obliterate him. Afterwards, the Tuatha Dé family adopts Dia under the guise of being Lughs younger sister, completing the mission. Sometime later, Lugh receives word that the Hero, Lord Epona Rhiannon, has arrived in the Alvan Kingdom.