Someone

    class MainRoot
    {

            public static var container:Sprite = new Sprite;
            public var playerLife:int = 5;
            public var gameLevel:int = 1;
            
            public function MainRoot()
            {
                    addChild( container);
            }
            public function SummonArmy()
            { 
                    pasukan:Army = new Army();
                    container.addChild(pasukan);
            }
    }
     
    class Army
    {
            public function Army()
            {
                    trace(detekTemanSeperjuangan());
            }
            public function detekTemanSeperjuangan():int
            {
                    var countUnit:int = 0;
                    for (var i:int = 0; i < MainRoot.container.numChildren; i++){
                              countUnit++;
                    }
                    return countUnit;
            }
            public function addGravity()
            {
                    //anggep aja disini nambahin gravitasi pake variablenya stage :p
            }
            public function tambahKuat()
            {
                    //anggep aja powernya disesuaikan pake variable gameLevel di stage :p
            }
    }