Strong Male Lead & Game/RPG-Like

Humans live in the overworld, and demons in the underworld.
There is only one way for humans to travel between the worlds.
Mankind's last hope: WARBLE.

Rai wakes up from 820-years long sleep and starts his new life as a student in a high school founded by his loyal servant, Frankenstein. But his peaceful days with other human students are soon interrupted by mysterious attackers known as the "Unions".

A story of an unemployed man that revives after three days of being dead. Follow his action-packed encounter with a large criminal organization.

Bam, who was alone all his life has entered the tower to chase after his only friend, Rachel, but how will he survive without having any special strength or power?
"What do you desire? Money and wealth? Honor and pride? Authority and power? Revenge? Or something that transcends them all? Whatever you desire—it's here." In The Tower of God.

Daeho Han needs money to save his mother. Jihoon Nam wants revenge.
The two join hands to take on the top 0.01% "super rich" class.

A weak and sickly boy, Sung Woo-mun's condition worsens when he loses his mental capacities, owing to a painting gifted by a sage. He grows up as the 'village idiot', pitied by his own parents. But unbeknownst to everyone, his life is about to change soon, and a new destiny awaits him. When Sung Woo-mun turns 20, not only does he have an epiphany, but an undefeatable martial arts power begins to bloom inside the painting.

Noh-Ga-Jang has led the life of a warrior ever since he remembers, isolated from the world and illiterate to top it all, til he meets a woman who steals his heart. He marries her and they live a life of bliss and she gets pregnant with his children. Against all odds, she dies during childbirth, leaving Noh alone with their newborn triplets. Desperate, saddened, but not broken, he swears to the heavens that he'll become an exemplary man to raise the invaluable treasures his wife left him.