In Diablo 3 (PC game) there is a weapon class called "heaven hand" (other weapon class names are more ordinary like "wand", "long sword" etc). I understand, being fictitious as it is, the name can be arbitrary. However I am under the impression that "hand of heaven" is the natural way of saying it while "heaven hand" may be an attempt to sound exotic or artificial. I wonder how the phrase sounds to native speakers.
Let's turn this into a constructive syntax and usage question by asking whether it's more natural to use a compound noun phrase (NP) like "heaven hand", in which "heaven" functions as an adjective, instead of the longer and, perhaps, underlying noun+prepositional phrase (N+PP) structure "hand of heaven", which is quite common in English and a host of other languages.
Both forms are common and correct. They're standard forms in English. Whether one chooses the long or short form is strictly personal preference, a style choice, not a grammar choice.
Which is more natural? I would suggest that context determines which it is. Native speakers of all languages like to shorten everything as much as possible, so there's nothing unnatural about calling the game tool "heaven hand". OTOH, in a church sermon, the priest or preacher will more than likely say "The Hand of Heaven will strike you down if you stray from the dictated path!" (I'm thinking of Cotton Mather and other fire and brimstone preachers here). Why? Because the rhetorical effect is more powerful; because it's longer and, therefore, has a greater effect on the reader or listener; because the important word, "Heaven", is at the end of the phrase and will thus linger longer in the listener's memory; and because it has a better rhythm (to me, at least) than "Heaven's Hand". Others may have a different preference, however. Style is personal.
I don't think the game maker was trying to be "exotic or artificial". I think the game maker wanted something short and easy to remember and preferred "heaven hand" to "hand of heaven". The icon looks like an object held in the hand. The game has other such weapon names, e.g., "Rageblade", which could just as easily have been "Blade of Rage". The game maker is being consistent with the weapon names.