To acquire the “How to Deckbuilder” achievement, we need to beat the final boss, Seraph, with a deck count of 0. This means we will have to purge EVERY CARD in our deck before our train’s pyre lands the final strike on the last boss.

This achievement can be acquired organically using many different methods but if you've already completed all covenants which each faction and you're like me; trying to platinum the game before the sequel comes out. You probably don't want to spend more time than you need just throwing hours away on runs that were dead on arrival when there's a more straightforward and consistent method.

That method is using community challenges! We'll be using the seed WarningsImpliedQuantum"for the community challenge created by the user Riantix.

This guide will walk you through the necessary choices to make to gain the achievement with a little room for some experimentation. This run is very simple if setup correctly.

The game plan is roughly as follows:

1. We MUST acquire the artifact Heavens Gold by entering the Concealed Caverns on floor 6: WildWood.
   
2. Prioritise every purge opportunity you get, no matter what you miss out on (exception for rule 1).
   
3. Save as much gold as possible, we will acquire an artifact in the run that increases the attack value of our pyre by 1 for every 10 gold we have. KILL EVERY COLLECTOR
   
4. We need to pick Titan's Gratitude from the Stygian reward pack after beating the boss of floor 1: Limbo, after that skip every reward (both artifacts and cards).
   
5. Accept every trial, be careful of the spike trial of floor 4: Waxen Arches

The run we will be using is a seeded challenge so we need to navigate to the community challenges menu. So from the main menu go: Challenges → Community challenges.
There's an input field labeled Join Challenge, we need to enter the seed:

WarningsImpliedQuantum

and then click the arrow icon.



We should now be at the Custom Challenge screen so click start run and then we’ll have the achievement in no time.

Our pyre has buffs from the challenge modifiers that grant it multistrike 1, +15 attack, +40 health and gains 15 armour at the start of each battle. Our pyre is our win condition and can handle most monsters up until floor 6 without us doing much but from that point on we need to make sure that the pyre can kill the monsters outright if possible.



If you’re in a fight and you mess up, just go back to the main menu (DO NOT ABANDON RUN!). Then navigate back to the community challenge screen and select the seed we used from the Recently Viewed challenges on the bottom right, then select continue run from the custom challenge screen and the fight will reset to the start of turn 1.

From now on, the directions provided to you will be what artifacts/cards to skip and what overworld paths/curios you need to interact with. How you play your cards during the fights shouldn't matter as our pyre can handle most of the monsters but do keep an eye on the monsters that have more health than what the pyre can dish out over two strikes.

Click the Herzal’s Horde and select Vapor Funnel. This artifact dazes the monsters by 1 when they enter the pyre room, allowing our pyre to land a 2 hit sweep before the monsters act.



Then get the party started by clicking the boss fight and accept the trial.



Our pyre is ‘roided out so we can literally just skip our turns without doing anything except turn 2 because we need to kill the Collector fairy for the 50 bucks.




After you kill the boss, skip the Hellhorned rewards, select Titan’s Gratitude from the Stygian rewards and skip the unit draft.

Grab the money from the Forgotten Boons then enter the Merchant of magic shop where we want to upgrade the Titan's Gratitude with Powerstone then purge 3 Train Stewards. Leave the shop and then enter the boss fight and accept the trial.






This fight can be skipped through pretty well but just make sure that the Conduit Redirector monsters are killed before they reach the pyre room else the pyre might take health damage which is not ideal. Always kill the Collector fairy.



Skip all rewards.

Activate the unit draft but then choose skip ‘cause we want that money. Then go to the magic shop, give Titan’s Gratitude another Powerstone upgrade and purge the last Train Steward so we’re only left with spells. Now go to the Concealed Cavern and give the Winged bloke the Titan’s Gratitude. We do this because it becomes our room-cleaner later on.





Select the boss fight and off we go again. Our pyre will strike for 60 damage a turn and all monsters (besides the boss) have less than 60 health so we can let it do its thing while we punish the boss with our spells.

Skip each reward and for our major enhancements either choose Herzal’s Compound or Fel’s Remorse. Herzal’s Compound will draw us more copies of Titan’s Gratitude when we get it back from the Winged for the late game room clear. Fel’s Remorse should help in boss fights 4 and 7 as there are monsters that add 1 ember cost, scourge cards to our hand that will deal damage to our pyre if we don't play them. I chose Herzal’s in my initial run.

Select the Hellhorned Banner and skip it for the money Then select the Unstable Vortex and purge a Forgone Power and a Torch card. Skip the Merchant of Steel shop.



Enter the boss fight and accept the trial but be warned; the 4 spike damage can become a problem if the we don't kill enough monsters and also the Absolver monsters will add a Weight of Contrition scourge card that deals 3 damage to your pyre unless played. My Strategy was to focus the Absolvers with Torches first then if I have free ember and spells, I use that to take out another monster to reduce the damage the pyre takes from the spikes.



Now that the fight’s over and your pyre should be over 100 health you should be good for the rest of the run otherwise it might get dicey. We now skip the rewards too (yes we took all that damage for 25 bucks, yes we probably could skip it but we’re greedy).



The Winged should return with our fancy new Titan’s Gratitude, I took it back from them at this point but you could skip it until the next boss in theory. The new variant we now have gives us that “send a copy to the discard pile” effect that I mentioned before and is a 1 ember room-cleaner that gives temporary copies when we play it.

This works great for our game plan as we constantly thin our deck throughout the run and we can make multiple temporary copies of it during a fight, effectively giving us a temporary deck of Titan’s Gratitude.

Grab the Forgotten Boons, select the Herzal’s Hoard and either skip it or grab the Tempered Talisman. Go to the steel shop and purge any card except our Titan’s Gratitude. Select the boss fight and accept the trial.



This fight we should try to use the Titans as much as possible on the larger health monsters or whenever we can. This fight should be much easier and quicker than the last fight.

Skip all rewards.

If you don’t choose the path on the right, it will effectively end your run.
Select the Concealed Caverns and choose the Aggressive! option and it will give us the Heaven’s Gold artifact which, as mentioned in our game plan, grants our pyre +1 attack for every 10 gold we have. Once we reach the final boss we will not have any cards in our deck so the pyre will be on its own, leading us to victory.



After that select the Unstable Vortex and purge any two cards. Then go to the magic shop, purge another card then we’ll move onto the boss fight.



This fight is also easy, our pyre should be doing at least 50x2 damage a turn and should be able to handle the monsters. Our job here is to spam Titan’s Gratitude on the statues first and take every opportunity we can to hit the boss with spells. You want to clear the rooms as much as possible to leave the boss open to Titan’s Gratitude. If you played your cards right and you didn’t have the “Li-Fel-less” achievement already you should’ve been able to unlock it here by killing here at least 1-2 turns before the final wave starts.

As for the enhancements, I recommend the Herzal’s regardless of what enhancement you picked earlier in the run but if you already have a Herzal’s then choosing Fel’s Remorse is also fine. I chose a second Herzal’s to draw more Titan’s Gratitudes during the 7th boss.

Grab the Forgotten Boons, purge two cards using the Unstable Vortex, purge a card at the Merchant of Trinkets. We should now have only two cards left in our deck; one is Titan’s Gratitude and the other is a Torch or a Forgone Power, either is fine.

Jump into the boss fight and accept the final trial.



This fight can seem difficult due to the SpellShield 2 on each monster but our goal here is to spam Titan’s Gratitude as much as we can and always play the scourges generated by the Purifier monsters. The pyre should have enough attack to deal with the monsters but we want to ensure that we can get the boss as low as possible using our copies of Titan’s Gratitude so the pyre can finish them off in one turn.

This is the final act of our run. You should have 2 cards remaining in your deck, if not, give it a re-run and make sure you didn’t miss anything info from this guide. By following this guide all the way to floor 8, I got there with 140 health and 635 gold which left my pyre with 113x2 attack. Hopefully you have more of each value if not equal to mine.

Use the Unstable Vortex purge both cards and take the Forgotten Boon. Skip both steel and trinket shops and hit up the boss fight.



We just have to skip through the fight as we can't do anything. Goodluck and hopefully this guide got you the achievement!

Comment below if the Heaven’s Gold event doesn’t happen for you at the Concealed Caverns on floor 6. When I was researching how to get this achievement easily, a lot of seeded runs become harder or ruined by changes from various patches so hopefully this seed remains functional indefinitely.