In terms of the mulligan you want to aim for card draw so cards like Backfire are perfect for the quest and rushing through the deck. In addition to this, Runed Mithril Rod is great kept alongside Backfire, because whoever heard of cheating mana as not a great thing to do. These two are the most important to keep regardless of matchup, and if aggro is a concern then any pick of early removal from Drain Soul to Touch of the Nathrezim is recommended.
Quest Enablers: Raise Dead - Nets you the value of bringing back health such as Spice Bread Baker or removal like Entitled Customer with the addition of procs to the quest.

Unstable Shadow Bolt - Nice single target removal spell meant to stave off early game aggression with the idea that with 6 damage, it will be enough to proc the quest. Late game this pairs well with Tamsin Roame to deal with bigger threats, and almost guaranteeing quest progression.

Stealer of Souls - Typically you never want to drop this without being able to get value from it, so turn 6 (or 5 on the coin) is where you’d like to see yourself playing this.

And of course as mentioned earlier Backfire is priority for the quest yep.

You may ask yourself, “But if I’m tapping and hurting myself, then how am I going to live long enough to see my quest go online?”

Well that’s simple really, with the likes of Touch of the Nathrezim, Drain Soul, Soul Fragments, Armor Vendor, and Spice Bread Baker; you’ll have more healing than you’ll know what to do with. Spreading out these healing resources is crucial to getting towards that win condition. Oh and Malygos is really nice for tutoring these types of cards out along with the concept of using that fatigue damage at the end game with your quest reward.

In the end, space out your removal and healing to live long enough to see your quest come together, and turbo draw through your deck with the likes of Cornelius Roame to start using your own fatigue against your opponent. Thank you for reading through this guide,and may questlock enjoyers have a great expansion.