Hearthpwn

Toxic Mist: I'd made a 2-drop for token decks before, but after Un'Goro was released I decided to retroactively scrap it and give another chance to an even older design. To me, pyromancy feels like the closest to nature magic in the game.
Dragon Roar: I figured the closest to a WoW Druid in Dark Souls would be the shapeshifting Dragonbros, and so I made this card which is inspired by their AoE staggering move and provides the class with some form of single target removal.
Great Grey Wolf: Even Druid is getting a weapon of sorts this time. The Greatsword Hilt (which is a neutral weapon, btw) is a nod to the Straight Sword Hilt you could ascend with Sif's soul in the game to make the Greatsword of Artorias, and the way it works is reminiscent of how you could use any other weapon (or in this case, a card like Claw or Bite) to forge the Cursed Greatsword.

Swordsman of the East: Apparently you're his new bodyguard. This could help you establish board control early by securing your value trades at the expense of your Health. I'm not sure it would work as intended, though.
Basilisk: The Aldor Peacekeeper to Hunter's Mark. A nice way to portray Curse and how it reduces your max Health without getting too complicated.
Avelyn: This is a very interesting design for a weapon. Hunters are probably the class that can most consistently abuse this kind of effect, so I made it a slow card, just like Piranha Launcher.

Undead Rapport: This is kind of a hybrid between Duplicate and Redemption for grindy Mage decks; it benefits the most if you can get both to trigger on the same minion (the second one would summon 3 copies).
Homing Soulmass: It's a bigger Arcane Missiles, but each missile gets a buff from Spell Damage, so if you have Spell Damage +1, instead of firing six missiles, you're gonna fire five of them, each dealing 2 damage.
Big Hat Sorcerer: Before the release of Un'Goro, I'd made a burn spell specifically for Freeze Mage, which lost Ice Lance at the time. Seeing how powerful Mage is right now, how they don't need Burn at all and because I wanted to make a card based on Logan, I decided to replace it with this. It can still provide you with burn, and while it's way more tame, it's also more interesting and flavorful in my opinion. The way it works mimics what the Tin Crystallization Catalyst (which drops from Logan after you kill his hollowed self) does to your spells in the game.

Silver Knight: A small minion that benefits a lot from buffs.
Maiden of Thorolund: More support for the buff archetype.
Abyss Greatsword: Like the weapon in-game, its Attack scales with Humanity (or, in this case, your hero's Health).

Magic Barrier: Kinda like a Conceal which also applies to your face, but only works against burn and doesn't prevent trades from happening.
Stone Guardian: He casts Tranquil Walk of Peace on the enemies nearby. I'm particularly proud of this design; I think it promotes interesting decision-making relating to positioning.
Pardoner: A very synergistic 2-drop. It can be played on curve but ideally you should play it after turn 4 combo-ed with a spell to get value out of its very powerful effect.

Death Roll: Fun spell that depends heavily on the opponent's positioning, just like Betrayal. EDIT: Now it starts from the right so it works better against spells that generate tokens.
Swordsman's Bodyguard: Fuck you Shadow Rager.
Darkmoon Blade: Weapon buff which synergyzes with Spell Damage. This is almost irrelevant in Standard but way more significant in Wild, and seeing as Rogues are shit in that format, I don't mind giving them some tools they can be abuse.

Chaos Fire Whip: There are three possible outcomes when you cast this spell: if your opponent's board is clear, it hits their face; it hits a single minion which is directly in front of your hero portrait; or, if your opponent has an even number of minions, it hits the two facing your hero.
Ceaseless Discharge: I really like to slap board clears into minions, and I think this one was a really creative way of doing it. It's worth noting that it triggers off its own Overload, so you should think of it more as a 6/4, not a 6/6.
Moonlight Greatsword: A weapon for combo decks, with a delayed effect that requires some setup but is also versatile.

Darkwraith: I really like disruptive effects, and I figured if it wasn't permanent and affected both players, then it should be fine and not that unhealthy for the game.
Karmic Justice: This one's totally different from the actual Dark Souls spell, but I figured after MSoG Warlock didn't need anymore removal than it already has. What it needs is healing, especially if this adventure were to spawn a self-damage-heavy version of Handlock.
Taurus Demon: Another card for Handlock. Maybe this could make Unlicensed Apothecary or Pit Lord playable.

Peddler from Zena: He sells exotic gear. Would probably be crazy after Justicar rotates out.
Golem Axe: It being able to bypass Taunt is meant to portray the ranged R2 the weapon has in-game. I honestly don't think you'd run this in every Pirate Warrior deck, simply because it has poor stat distribution for such a fast strategy (it's much better to have high Attack weapons to buff with Upgrade!), and also because Taunt isn't so prevalent. EDIT: After Un'Goro, Taunt is much more prevalent, but with this expansion I'm also introducing neutral healing, so I think it's fine to keep this as it is.
Knight of Thorns: Magnataur Alpha done right.

Titanite Demon: After it dies, you get Demon Titanite to upgrade your weapons.
Balder Knight: Sometimes he gets you by surprise or lands a parry on your attack and then ripostes you.
New Londo Ghost: In the game, you can only attack them if you're Cursed, which is why I restricted the ways you would be able to kill them in Hearthstone. Note that being Immune means that it doesn't take damage from sources that don't target, but it can be killed by cards like Twisting Nether and Deadly Shot which destroy w/o targeting, and can also be debuffed by Equality (though not killed by Pyro's whirlwind).

Royal Sentinel: If he takes too much damage, he stops attacking to heal himself.
Bell Gargoyle: Vanilla 5-drop that synergyzes a lot with Silence mechanics.

Fire Keeper: Her effect portrays how you can spend your Fire Keeper Souls to upgrade your Estus Flasks.
Channeler: I really don't know if this effect is balanced. I suppose seeing your opponent's entire hand is worth about 1 mana (though it depends on the matchup), but I don't think this card would see much play outside of Arena, so I just assumed it was fine.

Onion Knight: In Dark Souls, Siegmeyer of Catarina wears this exotic armor and has the Pierce Shield, which is a small buckler with a big spike that can be used offensively (unfortunately, it doesn't appear in the artwork). This card kinda does the exact opposite; it allows you to use your weapon as a way of defending yourself. Basically, it does the same as Misdirection: when an enemy attacks you, he takes damage equal to your weapon's Attack, and the latter doesn't lose Durability.
Banshee: She sends out a rallying cry for all the Ghosts in the vicinity to come after you. Originally I meant her to summon them directly from the deck, but I think it's better the way it is now.

Elite Knight of Astora: This card was inspired by Oscar. In the beginning of the game, he gives you five Estus Flasks; I figured gaining +5 Health was too much, so I decided to lower it to 3.
Stoneclad Bishop: While wearing his ring, you can carry more weight without getting overencumbered.
Giant Blacksmith: Might be that the game doesn't need yet another giant, but I couldn't pass this opportunity.

Solaire of Astora: He's always by your side, whenever you need him, you just need to spot his summon sign and call for help. Keep in mind you CANNOT use the Hero Power if you already have Solaire on your side of the battlefield.

Dragonslayer Ornstein & Executioner Smough: They enter the battlefield together and, after one of them dies, the remaining one gets stronger. I tried to balance this against Twin Emps; I think the fact that, if you draw both, you lose half the board presence, and the way they're statted (like 4-drops without Taunt) more than compensate for the powerful buffs you get if your opponent only clears one of them.

The Four Kings: If you can't kill them fast enough, you're gonna get yourself in trouble.
Quelana of Izalith: I wanted a Legendary that would promote Mill archetypes (*burning* your opponent's cards); this is what I came up with. Without Emperor, there's a limit to how much damage you can do, and since it would involve upwards of three cards for a mere 10-15 damage (20 at best), I think it is decently balanced.
Seath the Scaleless: Kind of a win more card, but I love the flavor; it fits perfectly with the actual in-game boss battle.

I decided to make a crossover adventure between the two games. It would take place right after One Night in Karazhan: at the end of the party, you, the (absurdly drunk) player, would start messing with the portals at the Spire, and one of them would transport you to Lordran, where you'd meet Solaire and join him in his quest to find his own sun, while at the same time, trying to find your way back home.

For that to work, I'd have to mess a little bit with Dark Souls lore, mostly the prophecy of the Chosen Undead, which I intend to be Solaire himself. The adventure also would probably have to end before the final battle with Lord Gwyn, since you wouldn't take part in it (unless you play as Solaire in the final battle, but then what happens after it?), which means I'd have to figure out a convincing way of sending the player back home after the battle with Seath the Scaleless. That's probably not too hard to do, since the Duke's Archives and the Crystal Cave are magical places; there's a good chance I can make it work just like that.

I wanted you guys to share your suggestions with me and help me figure out how to better structure this adventure. I already have an idea of what it could be like:

FIRST WING (RINGING THE BELLS)

Bell Gargoyle (+ a possible cameo by Hellkite Drake) -> Chaos Witch Quelaag -> Iron Golem (with Solaire as the Legendary)

SECOND WING (ANOR LONDO)

Priscilla the Crossbreed (I really wanted her to be a boss) -> Dark Sun Gwyndolin -> Ornstein & Smough (obviously the Legendary duo)

THIRD WING (THE DARK PLACES)

Great Grey Wolf Sif -> The Four Kings (which could be one of these different, "survival" battles, but then it couldn't be the Paladin Class Challenge as I intended) -> Gravelord Nito (with The Four Kings as a Legendary, 'cus there's already Kel'Thuzad in the game which pretty much takes all of the design space for Nito)

FOURTH WING (THE WAY TO LOST IZALITH)

Ceaseless Discharge -> Centipede Demon -> The Bed of Chaos (now, this one is pretty much guaranted to be one of those different encounters, and I wanted Quelaana to be the Legendary; of course, that means she would appear throughout the entire wing and request you to kill her mother and sisters, like in-game)

FIFTH WING (PURSUING THE DUKE)

Seath the Scaleless (actually, this is when he kills you and you respawn inside the Prison Tower, so more like another one of those survival encounters) -> The Crystal Cave (same as before) -> Seath the Scaleless (the actual boss battle and also the last Legendary)

As it is, the adventure would end at the Crystal Cave, and then Solaire would go on by himself. All wings, except the last one (since only the final boss is a standard fight) would have Class Challenges, and the entire adventure would be comprised of 45 cards like LoE and ONiK, if not more. Let me know what you think of it.