Dean doesn't have to look down to see the danger - the glow is bright enough that it reflects off Castiel's skin, blazes his eyes, and Dean growls low in his throat, frustrated and angry.

Somehow in his hands the sword feels warmer, almost vibrating, but maybe that's the adrenaline coursing through him. "It's over when you stop," he replies, lifting the sword this time like the weapon it is, however sheathed. "I am real, Cas, nothing else you're feeling is."