Variadic templates double-ended pack workaround

The following code compiles because I'm assuming that parent of Option<Parent, T, Rest...> itself has no parent.

template <typename Parent, typename T, typename... Rest>
struct Object {
    T item;  // T is item's type, while Parent is parent's item's type.
    Object<T, Rest...>* child;  // child's item type is the first type from Rest...
    Object<void, Parent, T, Rest...>* parent;
    void setChild (Object<T, Rest...>* c) {
        child = c;
        child->setParent(this);
    }
    void setParent (Object<void, Parent, T, Rest...>* p) {parent = p;}
};

template <typename Parent, typename T>
struct Object<Parent, T> {  // Has no child.
    T item;
    Object<void, Parent, T>* parent;
    void setParent (Object<void, Parent, T>* p) {parent = p;}
};

template <typename... Args>
using ObjectWithNoParent = Object<void, Args...>;

int main() {
    ObjectWithNoParent<int, char, double> object;
    Object<int, char, double> child;
    object.setChild(&child);
    Object<char, double> grandChild;
//    child.setChild(&grandChild);  // Want this line to work.
}

What workaround can I use so that I can replace the type void with a general type?