When you say “innate supernatural power,” you are describing ways in which the fictional world differs from the real one. These things don’t work in real-life physics, but they are still ordinary within the context of the fiction. The fictional world is governed by different rules than the real world is, but dragons flying or giants not collapsing doesn’t break the rules of the fictional world. Magic does bend or break the rules of the fictional world. An agent such as a god, monster, or magic user uses some supernatural means to alter reality according to their will, to create some effect that would not otherwise happen on its own (or, one might say, “naturally”). In D&D, that is typically done by altering the field called “the weave,” or by entreating another agent to do so on your behalf.