Watch Out for This Old Man

A young soul from another world merges with a dead old man who is over eighty years old. Different memories blend with each other. What kind of personality will be generated from two different life experiences? One is kind-hearted, timid but a bit wretched, and the other is decisive but selfless. Is he a him, or he, or not him, not him, some or both of them? Let's see how an old man travels across the city and suppresses all enemies.