Super nice idea, thanks a lot! When N'zoth came out I toyed around with a Menagerie Deathrattle Hunter, but this looks way more solid. Also the new format of the article looks great to me. :)

First idea, I hope it's not too close to grumpymonk's.

This is meant to support the Big Demon Hunter archetype that never really took off. Alandien is one of the three Demon Hunter teachers in charge of training new adepts in WoW. She was the first known female Demon Hunter in-game. [I had initially used Kor'vas Bloodthorn for this card, but Blizzard has made her a real card in the meantime.]

Congrats, MathU!

Mill Rogue is absolutely disgusting to play against. 5 turns stealthing their hero is just too much for me. 

Good luck to the finalists!

Kathrena Winterwisp?

[it's still DestroyerR's turn, isn't it?]

Sure! I'm planning to do the puzzles today so I haven't tried this yet, but as far as I know, it doesn't really matter if you only use the leftmost minion. The goal is to get all enemy minions to 4 attack. Celestalon said on twitter that he wanted them to have the same attack right from the start and 4 was the first value that somehow came together. It was also quite flavorful with the 4 parts of the achievement. So there's no big mistery here as far as I know. It just seems to be easier to only use the leftmost minion and getting all enemies to 4 seems to be a maths puzzle if you don't just follow instructions from people who have already solved it. I hope that helps :) 

Some behind the scenes info from Celestalon for those that don't follow the devs on social media ;-) link

He also did a Q&A about it, but there wasn't much new info as far as I could see. 

Update: this would be quite a challenge, but your effect might be very flavorful in Rogue. You could make it look like sneaking in a saboteur behind enemy lines who wreaks havoc if he isn't discovered soon enough. Problem is, Rogue is not meant to get AOE. :/

Maybe make it weaker, like 1 or 2 damage? If you find art for this, you might end up with a super flavorful 5 stars contender! 

So you're "pretty active in HS and the HS community" but you don't read patch notes of major updates and the articles on the front page of the dedicated homepage your visiting and you don't follow the social media channels of the devs. I don't see much ground for complaining about not being informed about this to be honest, but maybe that's just me. 

Hmmm. Quite hard to tell actually. I'll just walk you through my thought process.

First of all, the texts are different. I don't think it's a problem, but have you used the word "next" in the Mage card when you have left it out in the Priest one on purpose? If so, why? I personally prefer the Mage version but I guess both will work out. I'm just curious if there is something to learn here. Maybe Open the Waygate shenanigans?

Both art pieces are really great, the Mage one is a little better. Same goes for the names.

Both effects kinda make sense in the classes you've put them in.

Balance looks okay in the Priest card (that was pretty much my suggestion after all), the Mage card looks very strong at 2. You might get away with this because Flamestrike got buffed and the effect triggers only a turn later and under a condition.

So what decides this thing might be the flavor. I must admit that my brain beats my heart in this case because I see your Mage card as a sibling of Wildfire, one of my favorite cards in the game: both are at 2 Mana, epic and have gorgeous art works. Here comes the but: that art doesn't fit your effect very well. It looks like a fire spell that blows up an enemy, which is fine for the effect when it triggers, but it doesn't explain the delay. In your Priest card, there's no such explanation either, but that's okay, because it's a mind manipulation kind of thing and no explanation is better than a false one in this case if you get what I mean. So my heart is all in for the Mage card, but logic dictates to go with the Priest one. Good luck! 

I'm here, I just don't have a good idea. Thanks for keeping this alive. You don't have to worry though, this thread has always come back so far, even after weeks of silence. Sometimes people just need a break.

Literally piggybacking might be something like Crabrider.

Alright, I'll try one last time. The achievement was added with the big patch this week. You could have noticed it in game and made your inquiries online. Celestalon also started to tweet about this like a week ago with cryptic stuff. When the patch was live, he flat out announced that there was a secret achievement. Last but not least, there was dedicated article on the front site of this. Very. Website. I do think those were enough opportunities to take notice of the thing.

Regarding your first edit: like I have already explained, the hints are in the flavor texts of the 4 mercenaries and they are easier to solve if you look them up in different languages. As far as I know, the Druid one was pretty straight forward in Chinese. And yes, putting the two Eclipse cards into a deck is part of the solution. 

No idea what you are talking about concerning the sound. I haven't seen a part of the riddle that involves sound. The flavor texts are quotes, but you look them up on the card pages.

Finally I'd like to stress once more that this was meant as some kind of global sized scavenger's hunt. No single person was meant to solve this on their own. It was about working together. Like once people figured out that the Druid riddle was a maze, it was only a matter of generating the map. Everybody could have contributed to that. 

I wholeheartedly disagree. I was watching the WoW Secret Finding Discord channel when they solved the first two riddles and it was amazing. People from all over the world working together to get this done, it was so chaotic and so so beautiful. Granted, the difficulty of this thing is beyond crazy but that probably was the whole point of it: it was never meant to be solvable by any one person.

Some explanations for more clarity:

Step 1 was finding out that the flavor texts of the Druid, Warrior, Rogue and Hunter mercenary contain clues for the 4 parts of the achievement. I wasn't around at the time but I guess what makes them stand out is that the characters quote themselves in their flavor texts. 

Step 2: They hint at cards you have to play against the innkeeper. To find out which cards exactly are needed, people from different countries helped together because the hints were more straight forward in some languages.

Step 3: Solving the riddles themselves. Some people tried to apply really advanced math to the Rogue one but got beaten by trial and error people because no one knew what to look for. For Druid it was a matter of patience once someone had the brilliant idea that it was a maze. I mean: Hiding a fucking maze in a HS board state. This must be the most genius thing in the history of Easter Eggs. Warrior was the old classic of bringing the sheep and the wolf over the river. I'm in love and no, I haven't participated in any of it. Just watching it unfold piece by piece was amazing. 

Update: Rogue is solved, we're halfway there!

People are speculating Druid is a maze and Hunter has something to do with buying and selling items. They are trying to max their profit right now.

I can recommend using the WoW Secrets Discord channel. They provide a shared sheet with all the known info so far. All 4 puzzles have been found, so far only Warrior has been solved.

Edit: the links are in Celestalon's tweet

More feedback:

As Demon and Sinti suggested, I have given my Meditation card the Forbidden treatment and swapped the art for something darker accordingly. Sad to see that someone else picked up the Meditation theme in the meantime :(

Sorry, I've corrected that. 

The fact that everybody can do this and seemingly can do this NOW looks significant. Pretty sure it has to do something with the Core set, Mankrik and/or Battlegrounds. I'd be very surprised if none of those parts was related to BG. That might also be the part that is difficult on mobile. Blood Gem APM stuff?

Book of Mercs might also be a part, but only Rokara's story.