Everyone Else is A Returnee

Average college student Yoo Ilhan has always gone through life without being noticed by anyone, even God! So when monsters were about to invade Earth and God sent all humans to other dimensions to train with mana... he forgot Ilhan and left him on Earth for 1,000 years! Realizing his mistake, God sends the straggler two angels to assist him as he takes on the monsters, eventually turning him into an unstoppable force. Now that people have returned to Earth, will Ilhan finally be seen?