Secret/Beast Hunter was and will always be one my favorite decks.And with the success I found with it in the current expansion I felt like it's worth sharing it!What makes it so good is that it can generate more value/threats than most decks can deal with.

Deck Guide :

First of all thanks for checking the deck means a lot to me and hope you will like it,now to the guide.

The deck is a secret/beast archetype where you use your beasts while getting some support from your secrets in order
to outvalue your opponent.
And it is cause of the above that it does well both against aggro and control match-ups should you have a proper opening
hand.
Some of the combos that helped me win most of my games are Dire Frenzy Hyena Alpha or Unleash the Beast while sometimes 
I even did it to Springpaw to beat the aggro and have an some low mana rush minions to answer later threats.Huffer is another excellent candidate for Dire Frenzy since you get a charge minion with a 7/5 body!
While Master's Call is great try to use the second one after you used Dire Frenzy to increase your hand with useful minions
that have boosted stats.
Hunter's Pack is an amazing card,and one of the best hunter SoU cards, as well since the secret is always useful to use for Hyena Alpha and due to the limited weapons Hunter has in standard getting Eaglehorn Bow or Gladiator's Longbow is quite the value for the deck.
Considering Zul'jin , he is probably the best card in the deck and the later you play him the more the value you get from
this card.I won at least 5 matches caused of him since he creates both a board and fills my hand so if you play him late in 
the game try to have an empty hand since it will be filled by Zul'jin!
Also try to keep Kill Command to finish the opponent off since Kill Command x2 + Hero Power + Eaglehorn Bow = 15 dmg for 8 mana.

Concerning the mulligan it is pretty much the same both for control and aggro match up with a few changes.
You always wanna keep a secret(or two if you're playing second)and a low cost minion like Shimmerfly or Springpaw.
Eaglehorn Bow and Animal Companion are great for both as well but in aggro I usually keep Scavenging Hyena as well while
in control match ups I will keep Marked Shot or Unleash the Beast.
Should I play second and have a secret in my opening hand I keep a Hyena Alpha as well since I can use her at Turn 3
and Dire Frenzy her at turn 4 to have way more value later in the game as well.
Other than that I try to keep control of the board without using too much of my resources in order to not let his AoE cards
be of value.

That's all thanks again for reading my guide and let me know if you have any questions in the comments.

Special thanks to Khristophesaurus Dinosaurus for the amazing Deck Spotlight!

Special Thanks to Tommy Wave for the wonderful wavy deck spotlight!