I Forged the Myth of the Ancient Overlords - Chapter 24 - 0. Sanity hits zero_1

In the City of Crime, one law stands above them all: Only the strongest can live.

Year 2056, in a city in the Yuan Jiang Su Jin area. On top of a ruined, shattered six story residential apartment sits a teenager wearing a combat vest, militaristic trousers, and alloyed battle boots. On his back is a hexagonal shield and equipped is a blood-shadow battle knife. He sits there silently on the edge of the roof. At this time, the sparkling sky was shining and there was a refreshing breath within the air that blew towards him. However, there was only silence within the ruined, deserted city, with an occasional howl that makes your heart skip a beat.

- Description from novelupdates

In the fantasy world ruled by Matriarchy, Kael of the Ancient Moonstone House, was working as a guild receptionist. Throughout his life, he was protected by his mother and later, younger sister, who was considered one of the highest potential individuals in the Queendom of Elyria. One day, he hears that his sister has gone missing and his family has accumulated debts of over 127 million gold coins to the Bank. The Queen comes to his rescue, paying off his debts and in exchange, he has to marry her five daughters, who each excel in a domain of their own.Having the five imperial princesses and the Queen herself as the backing, Kael has become one of the most protected individuals in the Queendom. Little did his wives know that Kael had another identity. He is the most dreaded yet noble Assassin of the imperial city, “K,” one who hunts down the criminals who escape punishment either because of insufficient evidence or using their connections.Follow Kael's journey, as he navigates his life as the protected figure in the light and protector of justice in the shadows.

A young man with an extraordinary mind is off on an exciting adventure when he mysteriously wakes up in the body of a feeble slave-guy in a different, rich in quirks world.

The main character, a selfish jerk, would use extreme means to achieve his goals. However, he never allows his base instincts to overrule his sense of decency. He always pays back both good and bad deeds.

Will his (terrible/excellent) mentality help him make a fresh start? Will he get through misfortunes and hardships of the new world?