speedfreek

It's not in the comic, directly at least. There are many theories. One is that it will lead to the Scavenger storyline who come to wreak havoc in Alexandria. Another theory is they are a group called the Wolves who may either reference the Scavenger group for the TV show. Or it could be a whole new story line separate from the comics. They would be a threat to Rick's group. They are messed up and don't kill their victims to the point where they are "dead". Instead they carve the "W" in their heads as a badge when they turn.

Another theory is that it is an upside down "M" and it's Morgan's work. This one is the most unlikely since Morgan was way behind them and they run into the "W's" before Morgan would of made it to the area.

My guess it will be the Scavengers or a take on them. If you saw the sneak peek for the season finale it looks like all hell breaks loose. Darryl saw the fire/light in the woods this last episode. Who was that? The Scavengers/Wolves perhaps? If so I bet they get alerted by gunfire or the motorcycle and follow them back to the safe zone.

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