How to Complete Stranger in the Woods
You only need to defeat Klesta the Crushatrice (the big one) in order to complete this quest, but you can defeat the Cluckatrices (the smaller ones) to get loot and more experience.
You control Luso, who starts off as a Soldier. Have Luso use the Attack command when standing next to an enemy. But be careful, because Luso is weak. It's fine if he dies, but you can try to avoid his death by not putting him too close to the Crushatrice.
You also control a Viera White Mage and a Nu Mou Black Mage. The White Mage can cast healing spells, and the Black Mage can cast attack spells.
Cid is on your side, but you can't control him. When it is his turn, he will automatically move and attack.