Pillar of reality would be an object, or a person thet exists in every universe. It looks the same, no matter where you go, it may get a special powers, or just a title. Infinity stones are a good example of this kind of item, they exist in most marvel, universes, and are closely bound to the universes they come from. This property, could give a human powers like immortality, immense luck, from the universe protecting it, or some other powers, like control over some parts of universe. I got the idea, from a book called "master of time" where mc is this type of entity