It seems to me from observation and experimentation, that if it is within a spirits power to kill, if that is his office, the endgame of the spirit;
That if one curses with said spirit without instructing for death, a curse merely to cause severe illness or everyone in the neighborhood to hate the target.
The spirit will then operate at only a quarter of its normal efficiency and speed.
While perfectly capable of causing dramatic effects these only seem to manifest when pursuing the endgame.
Take the demons in the kingdom of night for instance. All with the goal of slaughter but they have different ways of going about it.
Kind of the reaction I got from Gorka when I asked if he may cause despair and betrayal without actually trying to slay the target and he was like ‘Weeeell, if I must’ and went about his task with the speed of a husband carrying out the garbage for the 1’000th time.
Corollations anyone? It would be interesting, this is my experience at any rate.