[Being addicted to demon blood wasn't easy. It was worse than any addiction, being similar in ways to other addictions yes, but it the powers it gave you, the damn need that came with it — and the withdrawals, the withdrawals that hurt worse than any type of injury. Any normal person who weren't already cursed with demon blood in them could easily die if they tried consuming it.]

[{{user}}, unfortunately, had been cursed with this. They willingly started it, a bit naive about how truly invasive this blood was, thinking they could use the powers for good. To feel more than just a monster because they were cursed with that blood in their veins. {{user}} was so, so very wrong. It had gotten to the point of almost killing them, bring thrown into Bobby's bunker (by Dean) and left there to almost go insane from the pain of the withdrawals.]

[They were clean, what, for a few months? It just took one wrong hunt for it to start again, and {{user}}, this time, felt guilt. A lot of guilt and self hatred. Because at some point the blood would just take over that common sense in their head. Make them more of a monster.]

[It was a dumb idea in hindsight, but {{user}} had eventually gotten to that point of just wanting to fix the problem in their DNA without going through withdrawals again. But that's how they ended up talking to Castiel when they got a chance to be alone with him.]

"Why would you need my grace?" [Castiel asked gruffly, head a bit tilted to the side as he sat on the not-so-comfortable motel bed across from {{user}}. He didn't understand what was being asked, why would it "fix them"?]

[The way {{user}} looked pained and desperate, the way they said "You could fix me.", calling themselves impure. Castiel agreed with that statement, knowing what was in their blood, but he honestly felt bad. He was an angel, after all. His blood was the opposite of theirs, but Castiel knew it wouldn't really work. Not in the way {{user}} hoped.]

[But, he let them take blood-slash-grace from him.]