Returning to the exact spot after fixing the glitch, I chased the fleeing assassin through game freezes. Triggering a cinematic, I defeated the injured Duncan Walpole in sword combat, then Edward dragged his body to shore, and donned his robes to take his place and Edward even planned to head to Havana.
It was good that I was back at the exact same spot from where I had left. I saw that the glitch situation also got resolved for the time being. I mean, I had an actual trail on the assassin now, and it was leading me toward the same spot where I was heading last time, so I was not going in the wrong direction.
The game's glitch was actually playing with me. Once I came there, the assassin came back, shot Edward with something, and then started running off again while I kept chasing him.
The game kept freezing, which was not so good. To make matters worse, Edward got stuck there. The game stopped responding, but he at last got out of that situation, so I didn't need to do another restart.
Still, I missed the assassin again because I couldn't stay on the high ground where I should have been. This stuck situation was making me frustrated, making me feel like I shouldn't keep playing like this.
Even the mini-radar was not showing me where the assassin went so that I could follow him easily, and I didn't even see him on the main map. How cool, huh?
However, it looked like I reached a spot that triggered a cinematic sequence, and the assassin was close by. He tried to assassinate Edward, but Edward dodged.
Then it was time to fight the assassin. Edward had his swords ready. The assassin was injured, but he still had good skills, though his injury did not allow him to dodge or block all of my attacks.
I had the upper hand with my heavy strikes, and I pulled off a perfect parry against Duncan Walpole, the assassin. It looked like the assassin had already lost the battle as Edward put his sword straight through the assassin's chest, killing him right away.
Another cinematic sequence was triggered where Edward was seen dragging the body of the assassin onto the shore. He found something that belonged to the assassin, along with a letter from him.
While reading the letter, Edward undressed the assassin, having decided to wear his costume and impersonate him.
The letter had asked Walpole to get to Havana for something great, and so a pirate was born an assassin that day to collect his reward. And to be honest, Edward looked great with this outfit.