Here is the full list of all 10 A Hand in the Darkness achievements.
Reach all ends
Reach Bad Relationship End in Rick's route
Reach Bad End in Rick's route
Reach Good End in Rick's route
Reach Bad Relationship End in Monty's route
Reach Bad End in Monty's route
Reach Good End in Monty's route
Reach Bad Relationship End in Damian's route
Reach Bad End in Damian's route
Reach Good End in Damian's route