public interface ILocalModel<Local, Remote>
    where Remote : IRemoteModel<Remote, Local>
    where Local : ILocalModel<Local, Remote>
{
    Remote GetRemoteModel();

}

public interface IRemoteModel<Remote, Local>
    where Local : ILocalModel<Local, Remote>
    where Remote : IRemoteModel<Remote, Local>
{
    Local GetLocalModel();
}

public class Hero : ILocalModel<Hero, HeroData>
{
    // Fields and other stuff ...

    public HeroData GetRemoteModel()
    {
    }
}

public struct HeroData : IRemoteModel<HeroData, Hero>
{

    // Fields and other stuff ...

    public Hero GetLocalModel()
    {

    }
}