I Don't Have A Sytem But I Have Skills

In the fantasy world where the god gives a system to make the people's lives greater when they turned 15 years old, there is this one guy that was not given his own system.

For 3 years that guy was barely living greatly.

But everything changed when he finally learned that he had an innate ability that can absorb a monster's skill and make it to himself.

At the same time, something worst had happened to him that was caused by a demon lord, thus he swore to destroy every single monster he would see and slay the demon lord by himself.