"Such a sudden void will attract many creatures more than willing to fill it. It's certainly best that it is you," Castiel agrees with a nod, closing his eyes as he senses the power around them and just beyond. "His absence has not gone unnoticed, which I am sure you feel. If you need any assistance with protecting this place, please do not hesitate. As blunt an object as I can be, it can be useful."

He opens his eyes and fixes Rukia with a small smile. "I have not, before Darrow, been exposed to many types of power other than Angel and Demon. Aside from the healing, the power is very similar. I am glad to learn from you."