He could feel the energy gathering around the other man, then feel it darting toward his own body and beginning to coalesce into something much more sinister than armor. It surrounded him entirely, giving Arty no way out, even had he wanted to disengage his target. That was the first mistake. Never remove all hope. Always leave a way out, even if that way is too small to actually be exploited. When you didn't, your opponent had nothing left to lose and there was no longer any reason to hold back, which meant that Adrian was in for a hell of a lot of hurt. As fast as he could think to form the spikes, Arty thought faster. Before they had even begun to visibly coalesce, a second burst of energy was sent into Adrian's body, this one potent enough that his grounded status would be irrelevant. The energy simply wouldn't be able to get out of his body fast enough, and this time Arty focused it, sending it straight to the other man's vital organs instead of rampaging aimlessly through his body. Not only would it stop his heart and seize his lungs, but his brain would be pumped full of so much electricity it would literally flash-boil itself from the sheer heat being generated. At least, that's what it would do unless he could muster some sort of nano-second defense to prevent it.
He wasn't finished though, and when he caught sight of the grenade rolling up to their right side, he pushed off the ground with his right foot and pulled Adrian onto his side from his previously face-down position, landing on top of the other man's left wing. Not only would this expose the nephilim's face and chest to the full force of the grenade's detonation, but it would also shield Arty himself from the explosion. With all his energy already focused behind him and on Arty, the other man had almost no chance of foiling both the electrical attack and the grenade's explosion.
If he did somehow manage to survive the next half second however, as well as retain the mental fortitude to continue his spike attack, Arty would feel a compression around his wrists, but little more than that. With all the energy coursing through his hands and into the other man at that moment, their durability would be far higher than any haphazard attempt at a counterattack would be able to overcome, though the spikes were another matter. If those managed to keep coming, they'd shred his jacket and the shirt beneath with ease, and continue on to puncture the skin and muscle beneath. Those that hit bone would be stopped dead, likely before they actually touched the bone itself, and even those that didn't wouldn't make it more than an inch into his flesh. Even so, it would no doubt hurt like hell if he had been capable of normal feeling, and even with his lack of sensitivity to pain, the discomfort alone would be immense.