All rounder samurai

This is a story that take place in the year 20XX where technology reached it peaked where anything was possible and the growth of technology stagerd for several decades. One day all human woke up to find every single of their technology gone and monster began running ramped. The horror didn't end there beacuse when every human killed their first monster one of 50 weapon appeared and the more they fight back against the monster killing them the stronger the swords get. After a couple of years human finally killed all the monster in the world and even building 10 empire but when thing seemed to be getting back to normal the world was under attack again by the same type of beast but this time they were stronger and able to activate some skill. 10 devil came to earth and each of went in one of the empire the huamn population drop again by 40% but in about 2 years they were all kill ecpect 1, it's name was the immortal beast and they were force to used some types of dark magic to seal the beast in a 1 day old baby and the only one they could find in time was a kid name Marcus. Treated like an outsider for having a beast that killed millions of human and surprising when he turned 15 years old he was banned from the village and had a only dead bounty on his head that was 200,000 Yan coin. Let's follow the story of a young kid that dreamt of becoming the samurai king, being betrayed then a year later the third wave of monster arrived.