So I looked through Street Magic pretty hard and I don't see any spirits with the possession or the inhabitation power. Does that mean I have to take the Ally Spirit metamagic or find a convenient Free Spirit to make a homunculus?

As I understand it possession falls under the dark paths its not designed for PC use.

I believe ANY spirit can inhabit a prepared vessel. The cost is in the materials to bind it and the vessel to hold it.

For PCs inhabitation is limited to Ally spirits. Possession is just a matter of picking the right tradition. Some of the threats have inhabitation, such as insects.

Figures. I just wanted to make sure that I couldn't summon a standard Tradition spirit and stick him in a homunculus.
I'll bet my GM would let me go on a metaplanar quest to find a friendly Free Spirit that's willing to become my Golem.

You can create a plasteel vessel for use by standard possession spirits. It just isn't a permanent inhabitation such as inhabitation would be.

EDIT: I think...

That's excellent advice for any subject to a GM. I have what I consider a very good grasp on the rules, and I feel there are cases where I would have to tell a player that I'm not comfortable enough with some parts of the rules to allow this player type at this time... I have yet to venture into posession as an example. It just hasn't come up...

possession traditions can be scary... they tend to have the most worrisome spirits, imo...

[edited for clarity]

...yes they do indeed.

In SR4 the possession ability is a global replace for spirits called up by summoners from a possession tradition. So if you're a Houngan, a golem crafter, a sailor scout, or a hedge witch then all of your spirits have possession instead of materialization.

There are traditions that do the same with Inhabitation, and the only one listed is Insect. It's normally presented as a threat tradition. But if you're willing to put up with the crazy, that tradition is playable as well.

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In either case, the suggestion to familiarize yoursel well with the rules in question are best not ignored. Possession traditions play by different rules than materialization traditions and ae strong and weak in some surprising ways. Putting a big fire spirit into a cerberus hound or cockatrice is a really scary melee combatant. But possession traditions are themselves short in total actions per combat, and really short in the mobility department (a possessed vessel has less movement options than a materialization spirit because it is stuck in a body and less mobility options than a regular human because it is dual natured).

Inhabitation traditions ar even more different than the materialization traditions. Each spirit you get needs to be "paid for" with a sacrficed critter, so you often have to adventure for each one if you don't want the cops coming knocking on your door. Furthermore, you get an ass-whupping posse of spirits who will all fight for you and use their cool powers and everything. But you give up having the normal reserve of 1 standard disposable summoned spirit to do that. So your spirit lynch mob is way more powerful than other conjurers, but losing spirits sets you back days, , and several felonies instead of 3 seconds of concentration the way it does for a materialization tradition.

It's a scaling trade-off of gains vs. potential losses: materialization traditions have the weakest potential spirit army in straight up combat, but they also lose the least when their spirits go down (conjuring up a replacement takes a complex action). Possession traditions have a better spirit army but they lose real stuff when their spirits are disrupted (like prepared vessels and even friends), and inhabitation traditions have the most bad ass spirit army of all and they get kicked in the nuts when their spirits get disrupted.

In the open-ended campaign, I wouldn't really put my money on any of them as "the best", though in any circumstance where you aren't going to have another adventure (the last episode of the campaign, a one-shot adventure, whatever), the Insect Hive is pretty bad ass. The trade off of having a private army of hardcore loyal spirits against having to care about each of your spirits individually only is a balancing factor if there's actually going to be a tomorrow where you do care what happened to each spirit.

Insect Traditions: Take Care of the Hive and the Hive will take care of You. The ultimate eusocial shadowrunner.

-Frank

Nicey, Franky T.
I didn't realize that (in the absence of initiation) you had to pick a specific tradition to be able to utilize vessels effectively at character creation, and that those traditions have their own drawbacks. That's a really important mechanic to understand.

Just checking... I think I got confused during the last big ally thread.

Can possession allies Inhabit? That's been my assumption all along. Or can only inhabitation traditions Inhabit, period?

Or does a possession ally "possess until disrupted", which is kinda-sorta the same thing as Inhabit?

Not to go too far off topic, but I still argue that any mage that can afford to sit on karma until then get a hundred or so can get an ally that eats IEs for breakfast. It might cost a couple burned Edge for the bind/bind drain, but it'd be more than worth it, for any tradition.

There really aren't any inhabitation traditions, only possession and materialization. (Barring threats, specifically insects)

The inhabitation power can be purchased for an ally by a magician of either tradition.

The errata for Street Magic will clarify that, during design, ally spirits can be given either Materialization/Possession (depending on the tradition of the conjuror) or Inhabitation at the initiate's choice (note - don't forget you now have to invest in an ally conjuring metamagic to get an ally in the first place). Inhabitation (much like Materialization and Possession) is not a power you can otherwise buy/assign during ally creation, so such spirits should never possess any combination of the aforementioned powers at the same time.

And what happens if the Ally Spirit of a Posession tradition destroys the host and emerges as True Form?

I think that what you mean is: "what happens if an Ally Spirit with Inhabitation destroys the host and emerges as True Form?"

The answer is: the host dies, its mind and body consumed or incorporated in the True Form and the Inhabiting spirit presents itself in whatever shape and form is appropriate for the ally being conjured and the conjurer's tradition it might even have the same appearance as the intended -now consumed- vessel but it has True Form attributes and abilities (making it in effect a Materializing spirit).

Yes, that means putting an inhabiting ally into a familiar might kill the nice kitty so squeamish conjurers should be careful.