[mayegelt]

Two questions 1 general and 1 specific, i have my own opinions on the answers but i'm looking to see if anyone agrees or disagrees. starting with the general one

Psychic Focus and Chaos Psychic Focus, if i have a daemon psyker and generate all my powers from one discipline would i get the primaris power of that discipline and his godly primaris power? In an example:
I have a ML2 Herald of Tzeentch who generates all his powers from the malefic discipline, he also gets the Tzeentch primaris power and, as this is not generated and done before the game begins, would he also get the malefic primaris power?
in my opinion he would due to the wording of the rules but it would be considered dickish to do so in a casual game

the second question is about Fateweaver
as all psykers can genarate powers from the demonology can he? and if so would he swap some of his roles on the other disciplines for roles on the malefic one (keeping track of which head rolled which power)?

Ok first off... if the psyker is from the CSM book he must ROLL 1 of his powers on his chosen god if he has one. If however he is from the daemon book then no he doesn't.
This has the weird affect that a daemon prince bought from the CSM codex can only take the primus for free of their chosen god, as he must roll at least 1 power from that god. However the same daemon prince bought from daemon codex doesn't have this restriction. He gains the primus of his god for free what is states as
"that model automatically knows the primaris power of the discipline that corresponds to their patron deity, in addition to any other powers it knows."
So as he could roll everything on biomancy he could take the primus from biomancy for free IN ADDITION to the primaris of his god.
Kinda stupid I know, but that's the way the rules is written...

As for Fateweaver... sadly despite the FAQ saying all psykers know daemonology. His heads each know 1 spell from 2 specific schools. So no you cant have daemonic on him. Same as if an item of wargear gave you a random pyro spell, you couldn't swap it for a malefic just as it is new.
Same goes for the scroll of Magnus does not mean you now need to roll a D8 because of Santic and Malefic being added to the game, they aren't added to the item.
Again, seems rather stupid, but will likely get FAQ at some point to make either lefty or right have access to it and the other one have access to Santic or something bazaar.

 

[mayegelt]

As I put above.
"So as he could roll everything on biomancy he could take the primus from biomancy for free IN ADDITION to the primaris of his god."

Same goes for horrors for instance who could roll on Malefic. Get a 2 - Darkflame. They would also get the primus for free - Summoning & get the Tzeentch primus for free - Flickering

 

[mayegelt]

I think the trouble is that RAW vs RAI will get in your way.
RAW says what I said.
RAI probably meant that their primus should always be their gods and no other for free.

 

[mayegelt]

The key difference is if you read the whole of what I put on post 2 of this thread. That CSM daemon prince HAS to roll a power on his gods table so yeah can only take the chaos focus (ahhhh poor him)
Daemon from Daemon codex does NOT have to roll any of their spells from their gods one. So actually have the option to make all their rolls on any table available to them.

"Chaos Psychic Focus
If a Psyker has a Mark of Chaos or is a Daemon of a particular Chaos God (see Codex: Chaos Space Marines or Codex: Chaos Daemons), that model automatically knows the primaris power of the discipline that corresponds to their patron deity, in addition to any other powers it knows"

So as they know this "in addition to any other powers" it means it adds this on top of all the others it knows.

It kinda conflicts with

"If during the course of the game, that Psyker gains a psychic power from a different psychic discipline, he immediately loses Psychic Focus (and the associated primaris power)."

What is written before it about the psy focus, but as the chaos one is written after it (exactly after it) I would assume that a line would have been put in to say "This replaces the normal Psychic focus" or something along those lines. Though they may have remembered that CSM have to roll 1 and a max of half on their gods table so would never be able to have a focus otherwise. But forgotten that Daemons are not bound in such a way to force them to roll any on their own gods table (apart from Plaguefather)

Though of course he is not learning a new one during the course of the game, he has been generated it before the game starts.