This is the optimal build for the event. The gameplan is to play a power on each turn while looking for opportunities to summon a better unit than your opponent.
For starting hands ALWAYS reroll your hand to -1. I've noticed most opponents will not redraw their hand but that is a rookie mistake as your likelihood to diversify your power base is far greater on the third hand AND will guarantee you the victory in a fatigue situation (as pointed out by Mail). If you can play a power you should. Try to play shadow sigils as much as possible in case of Champion of Cunning or Mystery. If you don't have enough shadow, play as many different power types as possible to stay flexible in our 5 faction deck. This is a mental game more than anything and will get your opponent overthinking what you could possibly have in hand.
The best plan is to random into Telut or Nightmaw, Sight Unseen (thanks to demlet) as they will make your opponent regret ever putting 1200 gold into the event. As far as playstyle goes, I would classify this as a tempo deck where you want value on every turn. With your passive you should easily be able to play a new unit each turn. Remember thinking too hard is actually detrimental, you want as few decisions as possible. If you have any questions let me know, good luck getting those 5 wins!
Gave this to JonahVeil and he got a 5-0 first try: https://www.twitch.tv/jonahveil
I made this deck though :)