If the fact, that ad hoc created deck beat second quest twice in the row does not convince You, nothing will .

Sky said:

I'm convinced if you play 100 games and win 99%.

2 games hardly count as a benchmark.

Sky said:

I don't see the deck as ad hoc. It is deliberately constructed to take advantage from on of Spirits strongest mechanics (discard pile recursion). It also isn't fool proof because without Lore the deck has to rely on luck, a mulligan, and delay tactics to make sure it gets the cards it needs.

Sky:

Have you played a lot of TCG's before? I don't want to sound snarky, but if you have you'll know that a mechanic has to be seriously abusive before most companies even begin talking about issuing errata. Just look over to the Warhammer: Invasion forums, which finally (after almost a year) have been able to get the game un-broken. Allowing you to play a few cards from the discard pile for full cost does not even come close to abusive. I think that once the deck is finely tuned, it MIGHT be able to win 60/40 against Scenario 2.

And, to quote page 27:

"A tournament deck must contain a minimum of 50 cards. Additionally, no more than three copies of any card, by title, can be included in a players deck. Within these guidelines any combination of allies, attachments and events can be used in the player deck."

And, later, under advice,

""A player should also make sure that all the cards in his deck belong to a sphere that maches at least one of the heroes' resource icons, lest he find himself with a dead card he cannot hope to play."

There is nothing barring a player from doing so, so the deck works. As others have said, the question isn't 'can you include an out of sphere card', it is 'Sneak Attack work out of sphere', which we have come to an almost unanimous conclusion that it does.

Don't forget the golden rule that the text on the card supercedes the rules of the game. And I'm pretty sure "Stand and Fight" specifically mentions that you can use it one cards of another sphere.

If this game would have concrete walls around its spheres, with no leeway at all to include cross-sphere use of cards, it would be a much less interesting game. For me, the benchmark of a game that got this wrong was Decipher's LotR-TCg with all their cards that were only playable on one specific character. And the four unique sphere concept of this game still worries me in that respect. For that reason alone, this deck with its inventive use of Beorn is already very good news.

I see no issues with playing it that way. Well done.

Update: I have played a few more times and have been beat hard. The whole deck concept is based solely on a mechanic that is difficult to get out but once the engine rolls then it works very well. A few inconvenient flips of the encounter deck or not having the Galadhrim's Greeting show up within the first few rounds means certain destruction. THAT TROLL WILL WHOMP YOU HARD WITH NO BEORN (PERIOD). So ... fear not.

Also as far as the deck construction goes the rules for deck construction are at the end of the rule book, which at no time limit your using of out of sphere cards. but it does give you a warning,

"A player should also make sure that all
the cards in his deck belong to a sphere that matches
at least one of his heroes’ resource icons, lest he find
himself with a dead card he cannot hope to play."

I can hope to play those cards...

As for the deck make up I used all the spirit cards I had and just threw in Gleowine x 2 and Beorn x1. That's it. Like I said a non 50 card deck but a good example of a 50 card make has been listed by CAlexander

Thanks CAlexander for the 50 card make-up I'll be sure when I get enough cards to play around with it further.

Iron-on Ghost, you are a genius and your combo is 100% legal. SaF specifically states you can pull allies from any sphere. I would't find it highly unlikely that FFG would errata such a combo away; combos like that are supposed to be what CCGs are all about. If deck building choices were obvious, the game would suck. Like CAlexander, I wonder if this is perhaps Sky's first deck-building game.

You do not need this combo to beat scenario 2.

I've been playing 3 games and won all of them using only spirit deck with 3 gandalfs. It is easy, you quest with Eowyn, counter all possible cards that can screw you (and some of them do nothing if your threat is low), keep threat down, around 20 and destroy all enemies with the sharpshooting hero knight. Important: do not touch the troll. You can play stage 1 for hours and nothing can hurt you, reshuffling your deck all the time, putting threat level to 0 value, prepare the board with your every ally and finally screw the troll with 3 gandalfs strikes (when you deal last hit you should have 2 gandalfs in hand). Then you procede to quest with the army of allies and in the same turn you finish 2nd part of the quest and go to stage 3, which you win in 1-2 turns. It is possible to do that with 0 threat and after playing stage 1 for 3 hours (if you have time and patience) you will have tons of victory points.

I know 3 out of 3 is not a big deal, but I'll play some more games and check if spirit wins all the time. The important thing is to not let troll engage you, so you can't finish stage 1 of the quest and during this stage you can go through the deck multiple times.