Here is the full list of all 34 Ashen achievements.
Wear each relic once.
Defeat the Elder Dark Sissna.
Defeat Sissna in the Children of Sissna mode.
Defeat the brute near Vagrant's Rest.
Hunt the corb near Vagrant's Rest.
Complete Flokir's journey.
Wear the Umbral Veil.
Reunite the Listener and Human hearts.
Leap into the dark portal.
Unlock all townsfolk outfits.
Defeat the Shadow of the Ashen.
Complete Vorsa's journey.
Complete Jokell's journey.
Untangle Sissna's weave at the Palace of Lathyrus.
Acquire all lanterns.
Construct all houses in Vagrant's Rest.
Complete Eila's journey.
Hunt a roamar.
Hunt a squork.
Discover the secret of Contemplation.
Unlock all crafting specialities.
Travel the shadow pathways.
Defeat Touma and Souma.
Defeat the Listener Matriarch.
Meet Kol the wildman.
Take a ride in Eila's barrel.
Free the Diasora pup.
Hunt a Deer.
Defeat the Elder Dark Ukkoto.
Hunt a rafet.
Claim Vagrant's Rest.
Defeat the Elder Dark Riak.
Defeat Riak in the Children of Sissna mode.
Acquire all Kol's armors.