Three years ago, he was the strongest "Daybreak" in mankind, but found out that the top management had a secret deal with the alien gods. He had his memory wiped and was reduced to a mediocre patrol leader.
Three years later, an accident allowed him to regain the incomplete "trophy system" - hunting enemies can be exchanged for power, at the cost of randomly extracting a piece of memory.
What's worse is that he was born with "Ember Mark": burning up his memory can unleash the ultimate combat power, but what is lost will never be returned.