关于工厂本质的问题

是否真的应该只在创建新对象时才使用工厂，需要考虑到以前的对象、工厂内部变量和外部变量？

我举个例子：

interface Zone{
    Enemy toCreate(String name);
}
class Zone101 implements Zone{
    final int enemyToIncreaseTheirDifficult = 3;
    int countOfCreatedEnemies = 0;
    int difficult = 0;

    public Enemy toCreate(String name) {
        if(name.equals("Zombie")) {
            if(countOfCreatedEnemies % enemyToIncreaseTheirDifficult == 0) {
                difficult++;
            }
            countOfCreatedEnemies++;
            return new Zombie(difficult);

        }else {
            return null;
        }
    }
}
class Enemy{
    private int difficult;

    Enemy(int difficult){
        this.difficult = difficult;
    }
}
class Zombie extends Enemy{
    int timesToReLife;

    Zombie(int difficult){
        super(difficult);
        timesToReLife = difficult + 1;
    }
}