Path to Godhood

Ryuhei Minamoto, an SSS rank assassins with tens of billions of dollars bounty on his head, killed a large number of people before he retired.

Now on his death bed, he didn't want to die due to old age, so he took his weapon that accompanied him through his assassination days and stabbed his heart with it.

That is the end of the world most dangerous assassin.

-Or is it?