Here is the full list of all 26 Othercide achievements.
Finish the tutorial by defeating all enemies
Defeat every boss in a single recollection
Activate all Remembrances
Defeat Suffering
Discover all story chapters
Defeat The Child
Have a level 15 Daughter
A Scythedancer has been germinated
Defeat The Maid
Defeat The Deacon
Defeat The Surgeon
Kill 300 enemies
Save a Bright Soul
Close 20 Synapses
Lose 400 HP because of reaction or interruption skills
Spend 4000 vitae
Resurrect one Daughter
Sacrifice a Bright Soul
Earn 5 traits on the same Daughter
Sacrifice a Daughter with one memory attached
Sacrifice a Daughter
Start a new Recollection
Add one memory to a Daughter
Close the first Synapse
A Daughter is killed in battle
Reach the chrono map