Here is the full list of all 50 Eldest Souls achievements.
Gain the Abyssal Eye
Gain the Blessed Hunter's Charm
Gain the Blessed Trueice Prism
Maintain 4 stacks of Berserker for 30s.
Finish the game without activating any Shard or Infusions.
Reach the ending without dying once.
Defeat Azikel, God of Light while taking 0 damage.
Defeat the Guardian while taking 0 damage.
Defeat the Watchdog while taking 0 damage.
Defeat Eksyll in Abyss Mode.
Defeat The Deer God and the Warden of Purity while taking 0 damage.
Defeat The Warden of Purity in Abyss Mode.
Defeat The Deer God in Abyss Mode.
Defeat Aryana in Abyss Mode.
Gain the Kindled Heart of Fire
Obtain the Empty Vessel
Defeat Drakmur in Abyss Mode.
Deliver the bag of crowns to Edelon.
Defeat Hyem while taking 0 damage.
Defeat Hyem in Abyss Mode.
Defeat Eos, God of Unity while taking 0 damage.
Defeat Eos in Abyss Mode.
Defeat Azikel in Abyss Mode.
Defeat the Guardian in Abyss Mode.
Die to a rolling log.
Defeat Eksyll
Reach the Steps of Ascension
Defeat Drakmur, the Nightmare while taking 0 damage
Defeat Drakmur, the Nightmare
Defeat The Deer God and the Warden of Purity.
Gain the Blessed Feather of Dawn
Defeat Hyem of the Frigid Waste.
Defeat Aryana, First of the Moon.
Defeat Aryana, First of the Moon while taking 0 damage.
Hit enemies with a Shard attack 200 times
Have at least 10 Windleaves active at once.
Reach Concord Sanctuary
Defeat Eos, God of Unity
Retry a Boss 10 times in a row.
Defeat Azikel, God of Light.
Perform 3 Perfect Counters in a row against any Boss.
Hit enemies with a thrust attack 200 times
Hit an enemy with Windslide, Berserker Slash, or Counter 20 times.
Reach the Crossroads
Defeat the Guardian.
Die to a Boss.
Talk with Rass
Deliver the harp string to Edd
Defeat the Watchdog.
Reach Crusader's Landing