Well, yes, but you only need to replenish the arcane ward if they break down your barrier. If they attack me I could replenish the ward as a reaction with "shield". If not I will have to spend an action to use agathys so they take cold damage and I regain hit points + my barrier or armor of shadows of course; but I´ll be a poor mage if they keep hitting me all the time (and survive "hellish rebuke") without me using misty step, invisibility, etc to escape or burn them into a crisp (which would give me temporal hit points due thanks to dark blessing).
If there´s only one melee foe against you you can simply shocking grasp/banishment/polymorph him and run away.
Armor of shadows would be to keep my barrier up between combats or when I´m not attacking without the need for resting. There are other nice subclasses you can pick, but these ones fit nicely the idea I have for the nerdy tiefling.
Last edited by _Vic_; 03/07/20 07:16 PM.