Well, the original rules for Spirit Imbuement in Shadowrun can be found HERE. This is a slightly boiled-down version of a discussion provoked by those rules – which is enlightening enough that it was worth posting as well as appending it to the original page.
J: About the elemental spirit binding: are the problems resulting in the merger primarily due to (a) people doing something really screwy and insane and (b) an imperfect bond?
T: Mostly its that the spirit tends to shape the body. A human body can readily handle, say, having heavier hair, bones, and bearlike claws. It doesn’t work so well when the liver keeps catching fire.
J: …Which goes back to point (b)? That is, things simply aren’t sorted out properly even with a spell to keep it fm going totally out-of-whack?
T: It’s more that things really can’t be sorted out properly by any known technique. Elemental body-patterns simply aren’t compatible with life as we know it. We can meld parts from different organisms with cross-species genetic transfers, transplants, and so on. No one’s ever successfully melded a functioning organism with a rock. The adaption spell both protects the body against the elemental effects and lets the body keep working around the rough spots. Without it, the elemental form tends to break down and absorb the human body – growing at its expense and becoming more powerful.
J: Which actually makes me think of a few things. See, if that’s the problem, I wonder if it can’t be harnessed for gain instead of, well, killing you.
T: Yes, you could try to stabilize at partway along the burnout cycle. It would be bad for your life expectancy and create a few other problems if you kept it up long-term, but it’s quite possible.
J: That wasn’t what I had in mind. I was thinking, since the elemental half tended to want to absorb the human half, what’s the problem?
T: It’s because it absorbs both the physical body and the human portion of the mind/spirit. Becoming an elemental is possible via metamorphosis, doing it this way just results in an elemental with some vague memories left over from the bonded period.
J: Well, that’s kinda what I was wondering. Can this be the accelerated process, jumping to a much higher force than otherwise? Secondarily, can’t the elemental form then reverse the process with magic, making a temporary human body to use and possess?
T: Yes, a free spirit elemental may be able to make a humanoid form to occupy: the human mind would still be dead and gone.
T: The spirit departs once too much of the neural structure is destroyed or changed: you can bind it to a talisman though, just like making a cyberzombie.
J: Can’t people use Metamorphosis to become an elemental/free spirit?
T: They can: that can transform their body and spirit, it isn’t trying to anchor it in another body – which is what the elemental has.
J: If someone attains an elemental form, can they use magic to make a human body to work through?
T: Yes: all the free spirit powers can be duplicated with spells.
J: And a character could speed up the transition to elemental form with the spirit binding?
T: Not normally: having an example internally won’t really change your spirit any faster. It probably wouldn’t help the body change any faster either really: the elemental is destroying it, not really transforming it.
J: Nothing in life for free, huh?
T: Not really, no. Sorry.
J: Why, precisely, does elemental bonding eat up your Karma? If the elemental aspect isn’t actually using it, where does it go?
T: It’s harder to gather spiritual energy because you’re already overcharged. Spirits don’t normally get karma of their own, so bonding with one cuts way down on the acquisiton rate. That’s why it matters whether or not it’s dominant. In practical terms, that usually means that a spirit-bonded character gets an immediate boost at the expense of their future potential for growth. Now, if they weren’t really planning a career of danger, adventure, and getting lots of Karma, it may be well worth it – or if they were weak to start with and wouldn’t have survived without a boost.
J: Another question: what would/did the spirits themselves say about this? Not just the little ones, but the Totems. I would think that Shamans would consider this an abomination, since it ties someone to the wrong totem (probably).
T: Well, totems basically have no relationship to animal spirits. Animal spirits are like minor elementals: shaped from astral energy according to a pattern. Elementals are patterned on human notions of elemental energy, watchers on their creators mind, and animal spirits on animals. They’re like nature spirits; not really individuals unless or until they’re kept around a long time and develop experiences and minds of their own.
J: That wasn’t what I asked. I asked what the totems would think about binding someone (whom, as far as they’re concerned, is a relative) to someone./something else which is not.
T: About the same as they think of Cyberware: animal spirits are not relatives of totems, they’re constructs.
J: You misunderstand; I was considering the human to be the relative.
T: Ah, basically just like cyberware – unnatural, but not really their concern. Bind to a construct of metal, bind to a construct of astral energy, use dangerous drugs – all about the same to them. Is all that any help?
J: I had been thinking about a character who was trying to become, well, something like an Exalt – human and fire elemental all at the same time. However, since he’d need considerable karma to pay for magical abilities, including initiations and enchanting, it seems unlikely to work.
T: Well, the easiest way is the initiation-metamorphosis route.
J: But that basically means that he’d never be able to afford the enchanting. Initiation soaks up karma faster than a sponge.
T: You could probably do most of the metamorphosis with a few levels of pre-game initiation. Call it “exaltation” and just go on from there.
J: It was kinda supposed to be the upgrade for the character who started as a neuroborg, once he got his body back.
T: Ah. Tricky there, since that’s sort of starting over.
J: Yup. Although, technically, once he’s no longer a neuroborg, what happens to his race pick?
T: Hm. It’s never really come up. You’d presumably get most of those points back, which would be enough to convert to a fairly powerful magician-type and possibly pay for a few levels of initiation. You could take them to start with and just call them “Latent” (and thus cheaper).
J: Well, that would work. I’d have to switch some disadvantages around, though. If you buy Neuroborg as race, do you also have to pay the cash cost or take it as “Freeware”?
T: Generally no.
J: Oh, oddly enough it seems that being a neroborg still gives you “base” physical attributes. I take it, that for no particular reason, these are permanent?
T: Yes. And no, there is no good reason for that outside of the fact that being changed back from a neuroborg is rare enough that I’ve never written any rules for it. After all, it would essentially be a near-total character rewrite.
J: Hehe. I understand. It just seems odd that neuroborgs can increase their strength with karma.
T: True enough: Most of them have stuck with mental improvements for just that reason.