User blog comment:KillRoy231/SPOILER's return/@comment-1031724-20181130184118

So it sounds like he retains his grace, much like Castiel didn't get his full grace or wings back when he was revived in Season 13. In that case, Dean letting Michael in eventually to possess him was all for nothing, and Dean won't do that again. So now he'll be the huge threat he was at the end of Season 13, causing destruction on a scale hitherto undreamt of, with no one able to stop him since Jack's not getting his grace back.

Hopefully Dark Kaia's spear can be used to kill him, and Nick with him this time.