Program.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Xml.Linq;

namespace XmlTest2
{
    class Program
    {
        static void Main(string[] args)
        {
            var _doc = XDocument.Load(@"XMLFile1.xml");
            QuestTargets q = new QuestTargets(_doc);

            var list = q.GetElementsByClass<Targets>();
            foreach (var p in list)
            {
                Console.WriteLine(p.grouping.name);
            }
        }
    }
}

public class QuestTargets : XmlElementHelper
{
    public QuestTargets(string fileName) : base(fileName)
    {
        Parent = "targets";
    }

    public QuestTargets(XDocument doc) : base(doc)
    {
        Parent = "targets";
    }
}

public class Targets
{
    public Grouping grouping;
    public Protounit protounit;
};

public class Grouping
{
    public string cooponly { get; set; }
    public string forcetocenter { get; set; }
    public string name { get; set; }
    public string count { get; set; }
    public string team { get; set; }
    public string area { get; set; }
    public string groupfilename { get; set; }
    public string rottype { get; set; }
    public string rotateunitorientations { get; set; }
}

public class Overrides
{
    public string displaynameid { get; set; }
    public string parent { get; set; }
    public string visualscale { get; set; }
    public string maxhitpoints { get; set; }
    public string initialhitpoints { get; set; }
    public string maxvelocity { get; set; }
    public string icon { get; set; }
    public string soundfile { get; set; }
    public string convertresist { get; set; }
}

public class Protounit
{
    public string cooponly { get; set; }
    public string forcetocenter { get; set; }
    public string name { get; set; }
    public string protoname { get; set; }
    public string count { get; set; }
    public string team { get; set; }
    public string area { get; set; }
    public Overrides overrides { get; set; }
    public string usequesttargetindicator { get; set; }
}

public abstract class XmlElementHelper
{
    private readonly XDocument _doc;
    private string _parent;
    private string _child;

    protected XmlElementHelper(string fileName)
    {
        _doc = XDocument.Load(fileName);
    }

    protected XmlElementHelper(XDocument doc)
    {
        _doc = doc;
    }

    public string Parent { get => _parent; set => _parent = value; }

    public T[] GetElementsByClass<T>() where T : class, new()
    {
        Assembly asm = Assembly.GetExecutingAssembly();
        var typeName = typeof(T).Name;
        var type = asm.GetTypes().First(t => t.Name == typeName);
        if (type == null) throw new ArgumentNullException(nameof(type));

        return _doc.Descendants(_parent)
            .Select(item =>
            {
                var p = Activator.CreateInstance(type) as T;
                foreach (var prop in item.Descendants())
                {
                    var pi = p.GetType().GetProperty(prop.Name.LocalName);
                    if (pi == null) continue;

                    object newVal = Convert.ChangeType(prop.Value, pi.PropertyType);
                    pi.SetValue(p, newVal, null);
                }

                return p;
            }).ToArray();
    }
}