Why didn't the cure complete the third trial?

Question

In Season 8, Sam and Dean try to complete three trials to close the gates of Hell. The third trial is to cure a demon, but Dean calls it off when he finds out Sam would die when he completes it.

In seasons 9 and 10,

Dean becomes a demon, and then Sam cures him.

Why didn't this complete the third trial? The storyline was resolved pretty quickly (just a few episodes), so I'm wondering if it is in fact resolved, or if Dean might not be completely healed.

Is there anything to suggest that Dean isn't cured? If not, why wouldn't this complete the third trial?

Answer 1

There are two reasons:

1. Each of the trials are accompanied by a short Enochian chant:

   Kevin: [I]t's just a few words of Enochian, but...

   Dean: Oh, here we go.

   Kevin: ...the spell has to be spoken after you finish each of the three trials.

   ^{Supernatural Season 8 Episode 14: "Trial and Error"}

   Since Sam doesn't recite the chant, curing Dean doesn't "count" as a Trial.

2. More generally, the trials have a severe effect on Sam's body, as Castiel notes:

   Dean: No, you're not fine. You haven't been fine since the first trial. That's why I called Cas.

   [...]

   Sam: Dean, I'm telling you - I'm okay.

   Castiel: No, you're not. Sam... You're damaged in ways even I can't heal.

   ^{Supernatural Season 8 Episode 17: "Goodbye Stranger"}

   

   ^{Image from Season 8 Episode 23: "Sacrifice"}

   Since Sam let go of all that energy at the end of Season 8, and since he's since recovered from the massive internal damage the Trials had caused, still no Trial. If they wanted to try and close the Gates of Hell again, presumably they'd need to start over.

Answer 2

There are two possible answer to this question, depending on what it is actually asking.

1. If you are wondering why the third trial was not completed, it is because Dean intervined with Sam completing his cure of Crowley because Sam would have died. Even though Sam had almost finished it, he did not say that the Enochian chant to finalize it.

2. If you are asking why the third trial wasn't completes after Sam cured Dean from becoming a demon, it is again because he didn't say say the chant, and because the trial period had ended over 1 season before. Dean becoming a demon has nothing to do with the trial, but instead the Mark of Cain, and since he still has the mark, we can assume that he isn't fully cured from his mutated blood hungry old self.

Now I'm pretty sure that number one is the answer to your question, because maybe you mixed up some of the names, or plot lines from different seasons. Either way I hope this answers your question.

Answer 3

One of six things could be the answer to the issue at hand.

1. Since the Mark of Cain caused Dean to become a demon, maybe since Dean still had the mark, he was never fully cured.
2. Since Sam had given up on the trials and stopped suffering the effects, the trials pretty much reset.
3. Dean never lost being a demon, and that he was just suffering from the effects of the mark that it was just temporarily suppressed. This could mean that his demonic presence was tied to the mark. This may explain why he couldn't bail in the form of smoke.
4. The mark was keeping him alive, not the fact that he was a "demon", which leads me to believe that Dean may never have straight up been an actual demon.
5. The necessary steps were not taken in order to properly cure Dean.
6. It wasn't exclusively Sam that cured Dean, and that Castiel may have also cured Dean, which may leave the third step incomplete, seeing as how Sam wasn't the one who actually cured him.

There may be something else that could explain it, but in the season 10 midseason finale, the effects of the mark resurface, but in the season 10 finale, Dean doesn't kill Sam, showing that he is not completely evil/demonic.