What about Serras getting found by the Dwarfs? or Settra?
Possible, but the former would probably dump her with the manlings if they were near the Empire(and not Chaos Dwarves), and the latter... yeah, enough skill with the Life and Death Winds would probably let her 'clone' bodies for them to move their souls into, and she could just do it again and again as time passed, since she would be all but immortal even with Beta-level feats as her limit.
I mean, if she can run multiple different psyker powers at once... maybe she can?
Eh, Elf minds are structured differently. Multiple Serras minds would probably end up more like the TTS Omake I made. It works, more or less, but it kind of has obvious side effects.
I can walk and chew gum at the same time just like every human wizard in Warhammer Fantasy, that doesn't mean they can do what the elves can
This. Different metaphysics are different metaphysics. Serras can brute force it to some degree, and it not being healthy can be overridden by literal engineering and Jade Magic, but she will run into problems if she has to do high-level feats with that kind of system to work with. Though, I imagine at higher 'Skill' levels she'd be able to rip the Dhar apart. On that note, I'd probably render the various schools of Magic as a tree of nine or so kind of like the early Perks, with Theory and Lore replacing Education and Esoteric, with the explanation being that every Mage had them, with Ice Wizards and the like having unique trees unlocked by their Class with certain disadvantages (Dawi Rune have their Rules, Elves have their passion and Dark Eldar issues, Chaos has the whole 'Could randomly mutate horrifically if the spell goes wrong.' Damsels and the like have to obey their faith's tenets or suffer power incontinence at best and outright backfiring at worst.) there, and unless you fell to Chaos the others were locked once you picked if you were a normal character, and the only opportunity for more supernatural powers there was to join up with a priesthood(Wind of Death and Morr seem like they'd get along pretty well, they both hate the undead.) and with all the anti-Mage prejudice to the point of often literally being in the lawbooks that would be incredibly difficult even if your Wind and the faith in question were completely compatible, which is rare.
As an abnormal character, Serras would be the exception, though Jade would, by default, by one of her first picks for the reasons mentioned earlier in the thread. She'd need a teacher, and she'd be under heavy scrutiny for being able to use multiple Winds without obvious Chaos corruption or going insane pretty much instantly.
Sure, but doesn't each discipline of psykery require a different thought process to use? Like Biomancy, vs Pyromancy, vs Technomancy?
It helps, sure, but a cold pyromancer could exist without major effect on their powers, just as a cheerful necromantic Daemonologist(That discipline is basically the budget-sorcery discipline that deals with souls, Warp deals, and Daemons, right? I'm a little rusty on the exact definitions.) could exist without it really affecting how many zombies they could send at you.
I don't recall that ever coming up, and I've read 40K books with psyker MCs, so I'm pretty sure co. People can have different talent levels with the various disciplines, and can use multiple, so no I'm pretty sure they don't have the same interaction method.
Also, using a discipline does not have the mental, physical, and spiritual effects on the one doing so as using one of the winds, which further differentiates them.
This, basically.