The crack of laughter that comes from him is... inhuman. Twisted bitterness that twines with his voice.

"Look, I-I get it, Dean will carve you in half with that blade of his if he finds out!" He's known the kid would have to lie. Needed him to lie, as much as he despised it. Because Dean hopped up on the dwindling sanity of the Mark and whatever laws dictate Abraxas, that blade might be able to kill Jack just as much as it might be able to kill Lucifer.

"But why Castiel?!"

That's where the pain lies. Castiel, who was the whole problem to begin with. Who swiped the container while Jack was still incubating and Lucifer remained bound to Crowley and Dagon again failed him.

He drops his arms and gestures wildly, the spike of anger coursing through him, but it's like overdosing on caffeine. Eventually it stops working. Eventually it doesn't absorb anymore.

"Anyone else. You couldn't have picked anyone else. Samandriel! They would've accepted that! Sure, he's dead, but there's... plenty of workarounds for that. Heck, there's multiple worlds. You had options and you had to go with Castiel?!"

He's entirely lost Jack's mention about wanting to get to know him.