You can excavate the top card, and if it is a "Dark Magician" or a Spell/Trap card that specifically lists the card "Dark Magician", add it to your hand. Otherwise, place it on the bottom of your Deck. During either player's turn, when a Spell/Trap card(s) you control is targeted by your opponent's card effect: You can banish 1 Spell/Trap card that specifically lists the card "Dark Magician" from your Graveyard; negate that effect, and if you do, banish it. You can only use each effect of "Dark Academy" once per turn.
I just thought of this when I realized how badly your whole strategy can fall apart if something so much as sneezes on your face-up Eternal Soul. Note that opposing field wipes like Judgment Dragon or even Dark Magic Attack can still bomb your Spell/Trap Card Zone, though.