Kane & Lynch: Dead Men

When a team mate betrays and kills another team mate in the alliance, they become a traitor. As usual, the person who dies leaves the alliance and respawns as a cop.

The traitor's Gamertag above their head will become orange. Once this happens, make sure you head straight for them to win the cash reward for killing them and the extra traitor kill toward this achievement. Walk over their body to collect their dropped cash (and for satisfaction).

These methods can be adapted for more people, but generally it's best to stick with 4 or 5.

Boosting method for 5 players courtesy of F4775:

We'll call the players 'Player 1-5' for sake of this guide.
player 1 kills player 2,
player 3 kills player 4,
player 5 kills players 1 and 3 for two traitor kills.

Player 5 could now escape with all the money to work towards the Mr. Play-It-Straight achievement and the 50 to Won achievement. Then again, they could commit martyrdom by means of a grenade to make the round end quickly. Rotate players so all get even kills for however many rounds or kills you need.

Boosting method for 4 players courtesy of MarkLaing07

Note that this method is less efficient than with 5 players; you'll only gain one traitor kill, but you do gain a personal revenge kill which could be of use if someone needs them.

Again, for the sake of this guide we'll call these players 'Player 1-4'.
Player 1 kills player 2
Player 3 kills player 1
Player 3 "cooks" a grenade
Player 4 kills player 3 and stands over the grenade to end the round

Tracking your progress

You can find the counter for your traitor kills in the menu; visit 'Multiplayer' and select 'Stats'.

Keep in mind that your personal revenge kills are added onto your traitor kills. To find out the true number of traitors you've killed, subtract the number of personal revenge kills from your traitor kills.

As the achievement description suggests , You need to kill 100 traitors in Fragile Alliance. (counts in Ranked or Player matches)

A traitor is shown in the game as someone who's name is Orange above their Character.

You can do this through regular gameplay in Kane & lynch everyone wants to get as much cash as possible. So Traitors are aplenty.

To rack up the Traitor kills hold back from the main pack and make sure your the guy that get's the kill when someone gets too greedy for their own good.

*Tip* make sure you host your own games, as a lot of people have it in there head that the money must be real or something and close down the session if they are losing , so if you get traitor kills they wont add to to your stats if session is closed Mid game.

Now if you want to boost these traitor kills , set up a session get a few friends in your session , Get one of your friends to kill the other friend (this now makes him a traitor) , you can kill him and hope you get out alive or to end the round quickly Hold out your grenade and get the traitor friend to kill you.

Your grenade will kill him, if it rolls away and does not kill him when you respawn as a cop make sure YOU take him down.

Make sure if you boost this way the guy who you want to get the traitor kill from , kills the other player before killing you so that the game registers it as a traitor kill and not a personal revenge kill.

It is possible to get 2 people a traitor kill in each round with just four people.

Player A kills Player B to become a traitor
Player C kills Player D to become a traitor
Player A+C both face each other and tap to roll a grenade towards each other
Player A is killed by Player C's grenade / Player C is killed by Player A's grenade

It takes a little bit of practice but is still incredibly easy. Also set it to only 3 rounds so that you can make some progress towards the Veteran achievement (200 games completed)