Here is the full list of all 51 Pyre achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Complete your quest for freedom (Campaign, True Nightwing difficulty)
Suffer defeat in a Liberation Rite (Campaign)
Complete your quest for freedom (Campaign)
Prevail in a Rite in no more than three dousings (Campaign)
Prevail in a Rite with 12 Titan Stars active (Campaign)
Prevail in a Rite with six or more Titan Stars active (Campaign)
Complete three Feats of Glory (Campaign)
Do Vocations 10 times (Campaign)
Using Volfred, deal 200 Pyre Damage (Campaign)
Unlock every chapter in the Book of Rites (Campaign)
Find an exile for each of the different masks (Campaign)
Liberate any three exiles from your party (Campaign)
Achieve Rank 5 with any exile (Campaign)
Prevail in a Rite against each of the other triumvirates (Campaign)
Using Bertrude, deal 200 Pyre Damage (Campaign)
Prevail in a Rite at each of the Celestial Landmarks (Campaign)
While flying, interact with 10 different observation points (Campaign)
Check 50 different pages in the Book of Rites (Campaign)
Prevail in a Rite with three or more Titan Stars active (Campaign)
While flying, bump into five different adversaries' wagons (Campaign)
Complete five Scribe Trials in the Beyonder Crystal (Campaign)
During a Rite, douse the adversary's Pyre by 40 health or more (Campaign)
Use Scribe Snuff to reset an exile's Masteries (Campaign)
Using Sir Gilman, deal 200 Pyre Damage (Campaign)
Using Pamitha, deal 200 Pyre Damage (Campaign)
Using the Stowaway, deal 200 Pyre Damage (Campaign)
Using Hedwyn, deal 200 Pyre Damage (Campaign)
Prevail in a Rite against a Master-level CPU opponent (Versus Mode, default Talismans and Masteries)
Prevail against a Master CPU opponent with six or more Titan Stars active (Versus Mode with default Masteries, Talismans, Pyre Health)
Prevail in a Rite against a CPU opponent while you have less than 10 Pyre Health (Versus Mode with default Masteries, Talismans, Pyre Health)
Prevail at the Isle of Khaylmer using Ti'zo and Messenger Imp (Versus Mode)
Complete a Rite against another mortal (Versus Mode)
Prevail using Rukey, Barker, and Dalbert (Versus Mode)
Prevail using Sandra, Tamitha, and Udmildhe (Versus Mode)
Complete a Rite against a CPU opponent (Versus Mode)
Prevail using Volfred, Ti'zo, and Oralech (Versus Mode)
Spend 1,000 Sol in the Slugmarket (Campaign)
Upgrade a Talisman to Rank 20 (Campaign)
Initiate 20 different conversations in the blackgwagon (Campaign)
Prevail in a Liberation Rite (Campaign)
Using Ti'zo, deal 200 Pyre Damage (Campaign)
Prevail in a Rite using Jodariel and Pamitha (Campaign)
Complete two Scribe Trials in the Beyonder Crystal (Campaign)
Using Rukey, deal 200 Pyre Damage (Campaign)
Prevail in a Rite without your Pyre taking damage (Campaign)
Complete a Practice Rite in the Beyonder Crystal (Campaign)
Using Jodariel, deal 200 Pyre Damage (Campaign)
During a Rite, banish three adversaries with a single Aura Cast (Campaign)
Use the White Lute to play a tune (Campaign)
During a Rite, fling the Orb at an adversary, then banish them within two sec. (Campaign)
Begin your quest for freedom (Campaign)