Now that I've beaten the storyline I'm working on getting my last few challenges done and this one is giving me trouble. Where is the best place to do this challenge without running into brutes and jagers that would ruin my streak?
I did this in Havana. As soon as you get off the Jackdaw, run up the dock and get the single guards attention, then run left and there should be 2 more. Keep running in that direction and a group of 5 or 6 come out and block your path. They all should be standard guys
I actually completed this challenge on accident, I was boarding an incapacitated ship, a frigate i believe, and was using my swords. You just need to gather up everyone into the center and just keep on spamming square and the occasion circle for countering.
You could also use the smoke bomb and pistol trick so you would use a smoke bomb and shoot and kill 4 people quickly then keep the combo going for another 3 kills with the hidden blade