When Thor heard his brother's voice, but did not see him, he smiled broadly, looking about. "So we are playing this game then," he said as his eyes searched the shadows. It had not been the first time that Loki had melded his physical being with the dark around them. Thor suspected it was how he occasionally spied on people in Asgard and learned their secrets. It had been amazing to find out just how many secrets there were in Asgard, so Thor thought that his brother was doing some sort of good by learning these things about others.
He had no want for this to end badly. In Thor's mind, sparring was a good way to heal personal wounds, to get out the anger physically and be spent afterward. It had worked many a time for him before. He still had a hard thinking of how others might want to deal with their anger. Of course, Thor knew that much of his anger was fairly easily dealt with. It was only more recent hurts that there were likely better ways to deal with.
But no, his brother was truly his brother here! Not so gone in his anger and madness. This was so much better than how Loki had left him. "I have a much better attention span than a rodent," Thor protested, twirling his hammer in his hand as he walked about, trying to get a fix on where his brother was hiding. If he was truly lucky, he might be able to draw his brother out by playing at being too stupid to find him. That had worked a time or two.
"Then why do you hide away, dear brother?" Thor called out. "I thought you were in the mood to fight tonight, or did you change your mind?"