Not sure if this deck is good. It's probably not. But I built it and then immediately went on a hot streak through Diamond 1 up to Master. Its tuned to deal with the endless aggro and FJS decks that I was facing. If you're facing different decks then change the cards that aren't good in those matchups.
Oh, and Mug is technically meant to be a way to punish FJS for making the exact same sequence every game as if there is literally no other option: Merchant for Tomb, play Tomb, Sabotage. Mug is the preemptive answer to that line, which is easy because FJS players are the most predictable players ever.
Dark Return
x2
1
Permafrost
x2
1
Seek Power
x2
2
Annihilate
x3
2
Strategize
x4
2
Vara's Favor
x4
3
Feeding Time
x3
3
Hailstorm
x4
3
Jennev Merchant
x4
3
Mug
x2
3
Wisdom of the Elders
x4
4
Deathstrike
x3
4
Vara, Vengeance-Seeker
x4
5
Champion of Cunning
x3
6
Black-Sky Harbinger
x4
7
Dizo's Office
x2
Primal Sigil
x6
Shadow Sigil
x4
Cobalt Waystone
x3
Crest of Cunning
x4
Feln Banner
x4
Seat of Cunning
x4
View Deck on Shiftstoned