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