the helm of serenity. Party is sane. Marten says
it does not matter when I ask him about any locations but tells the location of the Ascension Peak. I still need
the robe and the dagger, right? Those were at
the Rift and The Rapax Castle? I don't remember.
I don't think it works without having the robe and the dagger. And I have to go tell the Umpani
Sergeant about his men and give him the dog tags.

You are confused. To avoid to become insane you one of your team member must wear Marten's helm. Then give him the artifact marten gave you. Your team will then recover from insanity. You must not put it in the common inventory!!!

I'm not confused. I know how to cure the insanity.
My question was: Do I need the robe and the dagger
if Marten says "the Rift and The Castle are of no importance." This does not sound right.

those items are only used when you choose a bedfellow for al-rape-a-dude.. they have nothing to do with the ghost of marten.

What I mean is: Do you need them, the robe and the
dagger, for the temples at Ascension?

No, you don't. Only
the chaos moliri
The Destinae Dominus
and the Astral Dominae.