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