FishNet, you could usually trace him fairly precisely using the path, through ether or realspace, that his spell took. As is, however, you're almost completely drained, your arcane senses have just gone through what amounts to a firework display made of flashbang grenades, and the local field is drained enough that you don't actually have enough energy to set up the spell to redirect or cancel his.
...Well, you could, but you'd feed off your own life-energy and either die or become a quadriplegic, which I doubt you want at this point. It may look more appealing later, because I am entirely willing to let you lose if insufficient SMRTness happens.
However, you can certainly tell the general vicinity of the spell's origin, necros' territory is usually fairly obvious. If we sent a strike force, it would find him. On the other hand, the Mountainhomes have bigger problems than one outpost's zombie issue, and we only have around a hundred-fifty dwarves, which while a lot in-game, isn't very many at all by the standards of real life or worldgen, even armed with modern weapons, which they aren't.
Eye Spy scoutzed would indeed be either a direct link to the watcher's mind, or more likely to the creepy necromantic equivalent of a controller and display, which the necromancer is perforce right next to, but Eye Spy A Scoutzed is dedzed now unless our new friend wants it back on.
You can probably track the trail the energy took later, though if it went through the ether/aether/nevernever/fairyland/hyperspace/void/magical realm/whatever the path will likely get all twisty and weird within hours. Regardless, sending a force against him isn't really a good option right now, for a variety of reasons. One, he's stronger than you and Blaze together for reasons of fair, and two he really isn't our biggest long-term problem, trust me.
He doesn't have Joker Immunity, I'm just as fine letting you kill him as I am letting him kill us, but you'll have to be SMRT-ier than he is to pull it off.