Shovel Knight: Treasure Trove

I found Joustus to be 95% card power and 5% skill. You can’t possibly win against most of the opponents until you improve the cards in your deck.

This achievement should be one of the last that you earn in King of Cards and I assume that you have a basic understanding of Joustus.

I got this done on a second playthrough where I first got the Hurry Up, Beeline, and Naked King achievements (ignoring Joustus completely). I had already done a comprehensive playthrough for the rest of the achievements so I knew my way around the game and the basics of Joustus.

Your goal is to complete the four Houses of Joustus without buying new cards or reclaiming lost cards from Chester. The easiest way to do this is to find all of the easily obtained powerful cards from the later areas, then go back and play through the four houses. You also want to ensure that you don’t lose any matches so that you don’t lose cards since you can’t buy them back. The best way to handle this is to exit to the title screen when you see that you’re about to lose and try again. Since Joustus is turn based, it should be easy to see when a match is unwinnable before you actually lose.

Start by stacking your deck with these cards:

Homestead (use the Battery Brigandine armor to reach a secret area)
Mom
King Knight behind a breakable wall

House of Joustus
Cooper
Bard
Pay the bartender 5k gold to receive the Horns of Heralding.

Card Chest: Seer's Study
2x Level 1 Mystery Card
King Pridemoor

Cavern of Jostus
Troupple Acolyte
Chester

Card Chest: Gatherer's Grove
2x Level 2 Mystery Card
Troupple King

Crag of Jostus
Oolong from the Minion behind a breakable wall
Yoppler by using the Horns of Heralding to make a vortex appear, then dropping into it

Card Chest: King's Roost
2x Level 3 Mystery Card
King Birder

Fancy Shop/Void Crater
Mr. Hat

Tower of Fate: Shrouded Spires
The Enchantress behind a breakable wall

Tower of Jostus
Shield Knight and Shovel Knight behind a breakable wall

After acquiring all of these cards, my deck looked like this:


With your deck assembled, work your way through the four Joustus Houses: House of Jousus, Cavern of Joustus, Crag of Joustus, and Tower of Joustus. Be sure to exit to the title screen before losing a match so you don't lose cards and after defeating all 16 opponents and clearing the four houses, the achievement will unlock.

For reference, my deck looked like this at the end:


If you feel that you need stronger cards, you can defeat wandering travelers so that they appear in the Airship, then defeat them to take cards from them. You can also replay weaker Joustus opponents in the Joustus houses to get cards from them, but I personally had a powerful enough deck just from the cards listed above and any that I acquired as I progressed through the four houses.