Hearthpwn

I think this is my fastest possible version of a Sword of a Thousand Truths deck. There are lots of ways to build this deck, and I've tried many iterations.

This deck has 3 types of cards. Boar generators, Boar clears, and cards that draw. Let's talk about Boar Generators. The most important attribute for these cards is "Mana per boar". How many boars will you get for the mana you spend.

1 mana per boar

• Raise Dead - MVP because you get two boars from one card AND it's 1 mana per boar.
• Embalming Ritual
• Elwynn Boar

1.5 mana per boar

• Twilight's Call

2 mana per boar

• Resurrect
• Grave Rune 

More mana per boar

• Thrive in the Shadows or Shadow Visions
  
  • If you hit Raise Dead or Twilight's Call, it's less than 3 mana per boar which is pretty good. Also very flexible, let's you find boar clears instead if you have all the boars you need.
• Amulet of Undying - 3 mana per boar or cycle (in practice you'll rarely draw it twice)
• Insight - 3 (or less) mana per boar tutor

Mulligan

• Sphere of Sapience - Strong in the beginning of the game, not great later on. Keep it in mulligan.
• Elwynn Boar - Obviously keep any you find.
• Raise Dead - Keep this if you have a boar.
• I usually throw everything else away if I don't have a boar. Otherwise I keep my most efficient boar generators.

Miscellaneous

• You want to have a board clear by turn 5/6 so you can kill off the rest of your boars proactively. I usually get the sword online by turn 6, and kill them by turn 8.
• When you get the Sword of a Thousand Truths, do the math to figure out how many turns you can survive. Sometimes going straight for their face isn't correct, and you may need to clear 1-2 minions to slow down the rate at which you're dying. Don't worry about running out of sword durability, you have plenty of ways to generate more swords.
• You usually play Power Word: Shield and Shadow Word: Devour on enemy minions instead of your boars. You want your boars to die.
• You are hard countered by any kind of steal/transform effect. Be careful versus mage and shaman. You may need to hold a boar in hand for safety to prevent yourself from losing everything against a Devolving Missiles.
• Be wary of minions with freeze effects. If you get locked down you won't be able to attack with the sword. (Consider running Shard of the Naaru if you're having issues with that)
• I tried running two Dead Ringers but when a ringer draws a ringer it's pretty bad. Plus they dilute Twilight's Call and Amulet of Undying.
• I tried Teron Gorefiend but he doesn't work really well in this deck. It's not always easy to have 2+ boars on the field at once, he's really slow, and he's susceptible to transform/silence. You'd rather something that works proactively.
• I tried Wretched Reclaimer and Mirage Caller, they were both too slow or too niche, unlike the other more flexible cards.
• I tried Shadowy Figure but it can be clunky with Insight, and Insight is a better card for the deck.
• I tried Skydiving Instructor but it ended up as a dead card in my hand too many times.