Enemy Archers

Archers are the most common ranged enemy class you will encounter. They will shoot at your troops when approaching on their ship or when they are fleeing when your troops get too close. Their accuracy is around level 1-2 Ally Archers.

They are however quite vulnerable to melee attacks and other ranged attacks of any kind.

Travel in groups of 2-18, and rarely as a single unit

Basic counter: Infantry.

Strengths

 * Often in high numbers, which means lots of arrows.
 * Shooting into the backs or sides of your units.
 * Will often shoot on the run when being pursued, making even direct attacks with Infantry somewhat dangerous.
 * Attempts to maintain at least a 2 square distance.
 * Will shoot while approaching by boat.

Weaknesses

 * Vulnerable in melee.
 * Infantry is a direct counter.
 * Archers.

Strategy
The basic strategy is to have an Infantry unit to focus the arrows there and an Archer unit nearby to take them down. Only Infantry also works but Infantry can't block arrows while attacking, meaning there will be some casualties. Pikes perform very poorly against them without Pike Charge or additional help, so it is best to keep them away from Archers.

Given you have no Infantry or Militia, and the enemy's Archer's number isn't too big, you can send your Archers into melee range and use your Commander as a normal Militia. Do keep in mind, this is rather pointless and often lead to mediocre or even severe damage to your squad.

Link
*Source:http://badnorth.wikidot.com/enemy-archers