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