[Lucifer opens his arms and gives Castiel a slight headtilt] Unlike our brothers, I understand your cause. More than anyone. I can give you advice, guidance, and the comfort you seek. You see, Castiel, all of the angel's misunderstand me. They think I'm evil, that I wish to destroy things that are precious, but that's not it at all. I admit, I made a mistake with the demons and I fully intend to fix that, but I would never hurt an innocent creature.
[Lucifer looks down now, just slightly, but keeps his eyes on Castiel] You don't have to feel alone, Castiel. I'm here, and we're much alike. I would never lie to you, and I would only expect the same in return.