Hearthpwn

So, how does this mechanic work? Well, X is replaced with something, such as "Murloc" or "Secret". Let's suppose I play a Dragon with Dragon Exhibit, if I control no other dragon, the ability will activate. Unlike Battlecry, Exhibit triggers after the minion is played, so they can affect themselves. When you are holding an Exhibit card, it will have the Yellow Glow if the Exhibit can trigger. 

Cards like Deathcaller, Spirit of Fear and Follower of Zivius will give you Void Orbs when you play them, where you will store them until you use them. Void Orbs are store beneath your Mana Crystals just Overload, and you are capped at 10 Void Orbs.

Other cards like Twilight Embracer, Dragon Knight and Zivius are what will allow you to actually use these Void Orbs to your advantage. When you play a card like this, you can choose how many Orbs you spend. A Discover-like interface will pop up giving you options of numbers up to the number of Void Orbs you have (including 0 if you don't wish to spend any). The more you spend, the larger the effect will be, but use your Void Orbs wisely because they don't regenerate after you use them. Once they're gone, you'll have to play more cards to build these back up again.

While this image isn't a perfect representation of how I planned it to work, it should at least give you a good grasp of how it works:

Mana Surges are a new mechanic introduced in this expansion, and are generated by a whole host of cards. It's a 0-Mana Spell that does ABSOLUTELY NOTHING! But even then, it has a lot of uses. As a Spell and by extension a Card, it can be used to trigger on-play effects such as the Mana Wyrm and Violet Teacher. But if you want to use them as spells, that's perfectly possible as well - cards like the Nightborne Sculptor or the Naga Sorceress turn these seemingly useless cards into spells with their own effects.

Wither and Siphon are inspired by the ability of the Nightborne to absorb arcane energy and derive nourishment from it, and the fact that they begin to slowly wither away into mindless zombies the longer they are deprived from it.

Your minions are essentially 'Siphoning off' a tiny bit of your spell's powers. It's a scaling ability that is much more effective over a long game when you can cast more spells, draw more cards, and build up to larger effects. If you need to, you can also cash in earlier to get some more immediate impact. 

Wither is another keyword of this expansion. It's a versatile keyword that can be used as a debuff on enemy minions, or a downside on your own ones to allow for powerful minions that slowly get weaker as the strength drains from their bodies.

Elusive - This is simply the Faerie Dragon effect. I know Ben Brode said they don't intend to make this a keyword as it would be too confusing for new players, but hey this competition is just for fun and I want it :D

Chill -Chilled minions have a shimmering light blue mist surrounding their token. The Chill takes place at the end of each player's turn. This mechanic encourages trading; it's not often that a Chilled minion will last long enough on board to accumulate a ton of damage from the Chill effect.

Warm - Examples of this currently in the game are Nerubian Prophet and Shifter Zerus. Like these cards, your opponent will not see the trigger take place. I should note that most Warm effects encourage you to hold cards in your hand, however some are still stuck in winter, and will lose value as they Warm.

Here's how Nerubian Prophet looks with the new keyword text:

The sun icon tracks the number of turns a card has Warmed. In this example, Blossoming Nymph has been kept in hand for 3 turns and is buffed to 4 health. The icon doesn't appear on a card until the Warm count is at 1 or more.

Huge shoutout to ZardozSpeaks for helping me with this graphic!!!

It wouldn't be a proper Hallow's End without a heaping dose of terror! Fear is the set's new keyword that temporarily reduces a minion's Attack. Like Freeze, it expires at the end of the turn after which that minion could make an attack. So apply Fear to an enemy on your turn, it goes away at the end of your opponent's next turn. This effect can help slow down an aggressive opponent, or take the teeth out of a larger threat!

Traitors Secrets

The UI (user interface) when you play a card with Voodoo is like the Choose One cards UI. You pick one side and that's the effect you get. Some Voodoo add new effects and some replace the base effect (all ended in instead), you can see both examples under this lines (they're cards from Phase I). 

Remember: you can die if you don't have enough Health and you activate the Voodoo side of the card! 

• There would be a physical indication on the screen that a companion is linked to another card, so you would always have a good overview on who is with who.

• Silencing a minion would NOT unattach the companion or make it disappear.

• The master only needs to leave play - if it gets bounced for instance, the pet will disappear as well. This prevents some abuse.

• Silencing a companion WILL unattach it from the master. As most companions are smaller minions with useful effects, this will leave you with a weak body that (silenced) doesn't do much.