Mage tank

So an idea popped into my head watching the concept art stream recently. League has no true mage tank. I'm not talking about a champion that is good against magic damage. What I mean is a tank who's fantasy is all about the arcane and mystical aspects. I thought of a way to implement this so that you can clearly depict a mage but still have them be a tank. The tankyness wouldn't actually come from the character, but from spells she casts. Those spells come from an ancient book of arcane wisdom that she carries around with her. One spell could be just an aura that she can toggle on an off that can increase the tankyness of all members of the team, another could be a targetable shield or just a self shield, but I haven't come up with a full kit for this concept just a basic idea. I was thinking maybe giving the book it's own personality and having the mage hold conversations with the book in the game. Honestly this is a really unique fantasy that I want to see added to the game at some point. From everything I could come up with, this would be a support based champion since the aura would work best with a partner. Maybe make the aura just a manaless scaling passive based thing that you can turn off to improve the champion's focus to augment the other spells for a short time, and then it auto toggles back on, after the duration has been reached. Now that I think about it, this sounds more like an ultimate, so it would just need the basic abilities fleshed out.

I am pasting the section below from one of my comments as I was able to flesh out a more full kit.

Like, give her a targeted shield for a Q a stun of some sort for a W and a ranged taunt skillshot (perhaps throwing a rune at target location and all enemies attack the rune for a short time). With the defensive aura you get your natural tankyness and have it scale off of tank stats as if you were casting some of your tankiness onto your allies, and the basic abilities give you your utility.