Bloodfang has one of the most expensive abilities in the game, allowing you to summon an ally from your hand for free by paying 5SE. This effect is very strong, but it often only reinforces an already-dominant position, as you can't attack with the ally you summon. That is, unless you play this deck, and give your fatties haste with free haste attachments.

Hero: Bloodfang (45 cards)

Ally (20):
2x Bloodpack Shaman
4x Wulven Prophet
2x Wulven Predator
4x Wulven Tinker
2x Dark Riding Hood
2x Howlfang, Terror of the Vale
4x Crusher of the Weak

Ability (18):
4x Midnight Howl
4x Blood Moon
4x Captured Prey
4x Will to Fight
2x Confluence of Fate

Item (2):
2x Eye of the Dark Forest

Location (4):
4x Lakmire: Training Outpost

Deck Code: 1544977B

The idea of this deck is to abuse Wulven Prophet, a card that was recently buffed, and allows you to search attachments even if you already have one out on the field. This buff lets you run Wulven Prophet with Confluence of Fate, which lets you draw a card for every attachment you summon. Since you run so many attachments, we also use the location Lakmire: Training Outpost. This card lets you summon an attachment for 3 less on your turn, as long as you control only Wulven allies. This is not a problem for this deck, since you run only Wulven allies anyway. Locations all come with a downside, which is that they let your opponent gain an effect that they can use as well. Lakmire allows your opponent to reduce the attack of one of your allies by 2, and remove its passive abilities. This makes Lakmire difficult to use in decks with say, Wulven Tactician, but because most of the allies we run don't have passives, this actually isn't that much of a drawback.

This deck does extremely well against slower decks that can't deal with your hasted fatties- you have 8 haste attachments, and can sometimes close out the game before the opponent can retake the board. If the opponent plays a fatty or 2, you can disable it easily with Captured Prey, which gives you time to hit the face. Unlike most wulven heroes, this deck tends to do well against Mages and Elementals as well, since you can dodge effects like Mind Control with Midnight Howl, which returns fatties to your hand. The deck does best against decks that spam 3cc allies without steadfast: Wulven Crusher can exile them while you hit face.

Your best turn progression looks something like this (going second, going first you may have to skip a sac at some point to make Prophet live):

T2 Blood Moon
T3 Prophet + Lakmire + Confluence of Fate
T4 an ally + Captured Prey
T5 Bloodfang ability + Will to Fight
T6 Fatty + Will to fight/midnight howl

Weaknesses of the deck: If an opposing Braxnorian Soldier or Towering Brute sticks on the field, it can be extremely hard to counter. Additionally, this deck is weak to Covert Op, as it will interfere with Lakmire. There are a few tech choices you can consider:

Eye of the Dark Forest: This card works well against Brax, and only costs 2cc. I like using this card with Dark Riding Hood, as this way you can steal a card from the opponent's deck as a bonus.

Death From Above: This is the best way to deal with Towering Brute, as it also only costs 2cc, and is an ability.

Pathfinder's Machete: This card lets you beat Moonstalker. Props to Andy for pointing out this tech choice.

How competitive is this deck?: In my opinion, this is on par with other meta decks. It's a difficult deck to learn, so if it doesn't produce results immediately, you should keep trying the deck until you get the hang of it. I've won a pop up (the finals were a Haste BF mirror match), the pop up on the test server, and several high stakes tournament games with this deck. If you try it, let me know how it goes for you, and any changes you would recommend to the deck!