"The protagonist is invincible + training + multiple heroines"
Twenty years ago, a meteorite fell. Fragments of stars fell into the world, and spiritual energy revived. Affected by this energy, the area of the Blue Star also expanded ten times.
Monsters underground in the abyss suddenly resurrected, and surface creatures mutated.
Ten do not save one, in a critical moment.
A mysterious man in black robes called himself Jhin and took out tens of thousands of awakening stones. With Jhin's help, awakened people appeared all over the world. After two years of hard resistance, the alien creatures on the surface were defeated. Jhin faced the abyssal alien species alone and sealed it.
Very nice, really nice