It's inevitalbe that you are going to have to fight at some point. If it is not against a Walkier it will be against other survivors from other communities who like you are trying to stay alive. There is just not enough Food, Scavenge, and Lumber Fuel to go around so you are left with the option to either fight for it or die.
Survivors have four core stats that dictate their effectiveness in different situations:
Attack
Determines the damage done to enemies.
Defense
Determines the amount of enemy damage the Survivor can absorb.
Accuracy
Dictates the chance that the Survivor will deal damage to an enemy.
Avoidance
Controls the chance of the Survivor avoiding enemy damage altogether or lowering accuracy.
There are four classes for Survivors, each of which is strongest in one of the core stats and weakest in another:
Enforcer
Strongest in Attack, weakest in Defense.
Guard
Strongest in Defense, weakest in Accuracy.
Sniper
Strongest in Accuracy, weakest in Avoidance.
Scavenger
Strongest in Avoidance, weakest in Attack.
It is important that you master the chart below because knowing what Survivors to send is almost as important as making them as strong as possible.