I Am Retiring, but the World Is Ending

"I was a killer. Because of love, I gave up my bloodthirsty life and chose to marry her and live a happy life... Then she left me first... Then just retire and wait for death... It's the end of the world! I originally wanted to continue to provide for my retirement, but a series of changes forced me to survive... Because I want to protect her past. " ——An old man's thoughts