This deck combines the hignlander hunter and quest hunter in a decent way that works great in most games.
Mulligan: Keep all 1-3 cost cards except unleash the hound. If you have 2-cost minion, then don't keep springpaw. if you have the coin and licensed adventurer maybe you can consider keep Brann to play him out on turn 5 with 2 coins which is a very strong play imo.
In general, there are two winning strategies for this deck:
If you have many on-curve minions, i.e. a very good starting hand or a very good drawing, then you should be aggresive and go face. Otherwise, you probably draw many quest-related cards like Swarm of Locusts or Shu'ma, then you should consider finishing quest first and then go face.
Usually game ends on turn 7~9, either you lose for low health (vs face hunter) or you cannot control the board (vs rogue/priest/warrior), or you win with the strategies mentioned above.
vs. Big Druid https://hsreplay.net/replay/e2rKDztnUcB7Bbf7nGPDt9
Zephrys on turn 2: In most cases I choose Animal Companion as it fits this deck's winning strategies best. It summons a minion, and can usualy deal some damage while making your board stronger.
Dragonbane: try to play it on turn 6 not turn 4. If you are on low health, remember that the 5 damage also heals you if it has Zilliax's Lifesteal.
2/7: Hit rank 3, wr is still ~70% (43W - 18L)
2/9: Some tweaks. Now run with Ashmore, Flark and Primordial Explorer. This change will make this deck more consistent and lower the chance of losing board control on the early game.
Mostly lose to face hunter and priest.
Some replays if you are interested:
vs mech paladin: https://hsreplay.net/replay/pE9KxSwrw2nNBYgSbvZAJg
vs highlander hunter: https://hsreplay.net/replay/7LSqNHTRJU2XH7EjFmo4QL
vs Big Druid: https://hsreplay.net/replay/QGKg2ZxxYTfzTcujFehr43