After Retirement, I Became My Enemies' Nightmare, Free of All Restraints

[Power Fantasy] [No System] [No Goody-Two-Shoes] [Decisive and Ruthless, Merciless to the Core] After returning from retirement, he discovers that his younger sister has been tricked into going to northern Myanmar. He goes completely berserk and turns into a killing machine, growing hardhearted and ruthless. Decisive and merciless, with nothing left to hold him back, he encounters a group of like-minded "lunatics" along the way and unleashes a frenzied feast of slaughter.