Boundless Necromancer

Seong-yun Han was just a boy when his parents were killed by monsters unleashed during a mysterious calamity called the "Dungeon Break." Seven years later, Seong-yun is devastated to find that his grinding efforts to become a Hunter, fierce warriors who seek out and destroy monsters, are entirely in vain, as his fighting attributes have not increased at all. Seong-yun's world flips on a dime when he accepts an invitation to join the Tower of Trials, an otherworldly realm where challengers must overcome trials that pit them against monsters and humans alike.