I've been playing Oblivion for years now, and one item that has always facinated me is one you can never get through legitimate methods (only by console and mods).

The Grey Aegis.

It's basically a cheat item if you are playing a Mage; but for the NPC using it. 100% resistance to magic. I would put it simply down to game mechanics, but the Blade Master also mentions it does this, and frankly it seemed odd that Mages would be singled out. Without conjuration this turns the fight into a real pain for a pure caster. If you DO get hold of it through some method or other you have little to fear from any Mage the entire game.

But I want to know more from a lore perspective. Surely an item enchanted in such a way would be worth a fortune? Surely it would have a background beyond some Altmer Arena-Hero buying it from Stalwart Shields? I can find nothing about it anywere except what it does and ways to get it, all of which I already know.

On a similair note; if something this powerful can be created and fall into the hands of an Arena fighter, what lore-wise is the limit to enchanting? I'm still skeptical over the shields possiblity, but if it is do-able then isn't the sky the limit basically? A sword that gives the wielder flesh that cannot be pierced/damaged by normal weaponry? It just seems a little too... 'much' for a fantasy settign that i've only recently learned has a deep lore.

What you're talking about are mostly game mechanics. In Morrowind for example, resistance to magic didn't protect you against the elemental stuff. In Oblivion it does. I assume this has something to do with balancing the utility of the spells.

So the Grey Aegis may or may not protect you completely against magic. It being a shield might even only protect you from magic in a particulair direction. Yet with only game mechanics, there is no real lore perspective to go by.