Perform 5 Ground Finish in a single session of Manhunt as The Brigand.
The Brigand is the female character with the green (default) outfit, a cape, and a spear. On the selection screen she is the 3rd down on the left side (4th down when viewing the characters in the data hub, thanks xXDobleEquisXx).
Out of the 4 achievements in the DLC pack this one is, in my opinion, the most difficult. I say this because unless you're boosting this you're mostly at the mercy of the other players doing everything right in order for you to achieve it. Thankfully you can earn this achievement at any level so if you haven't reached level 20 yet you can work on this one while you build your XP toward the "True Templar" achievement.
I don't know how familiar you are with the multiplayer modes so I'm just going going to assume you know very little and cover all the important information, feel free to skip any part of this that you don't need.The Setup
In Multiplayer mode you'll want to select "Custom Match" (this can be done in a private match also if you have a group of friends that want to play), set it for a "Team" mode and then select "Manhunt".
If you're not lucky to be the player from your team to select the character you'll just have to keep your fingers crossed that the team leader will pick the Brigand. Alternatively you could try asking them nicely to select the Brigand for you, or you could could team up with some friends who are willing to help you out.Performing a Ground Finish
Manhunt is split up into 2 rounds, during 1 round your team will be trying to kill the opposing team, during the other round you'll be trying to hide from the opposing team. Which team does which first is random. A ground finish can only be done when your team is trying to kill the opposing team.
To get a ground finish you'll need to wait until one of your teammates makes a successful kill. If you're near by you'll see an X button prompt appear above the victim's body, run up to it and tap X to perform a "Ground Finish".
You'll need to do 5 of them in the same session, the achievement should pop the instant you finish the 5th.Strategy
Since you have to rely on your teammates to make kills for you to finish off, the best strategy is to identify the best player on your team and simply shadow them. Finish off everyone they kill, and help out by reviving them if they get stunned or locking targets if you identify an enemy.
If you're teaming up with friends you could all travel in a group and designate who will do the killing and who will get the ground finishes.Other Considerations
Unless the other players on your team are amazing you'll barely have enough time to get 5 Ground Finishes in a single match. This means you'll want to be playing from the very start of the match as opposed to joining a game in progress.
For this reason even if you find yourself on a team that is playing as a character other than the Brigand, stick with it, to make sure you're there for the whole next match. Also, after a few matches with the same group you'll probably find yourself the team leader and be able to pick the character you want.
While not the best, I do find that Manhunt tends to be pretty good for earning XP anyway. I was able to get a good chunk of progression toward level 20 while waiting for the right conditions to earn this achievement.
I welcome any other tips or strategies for earning this achievement. Thanks for reading!