Here's the definition, and pros and cons, of a fetch, taken from the RQII rules.
A fetch is a shaman's guardian spirit, which is usually related in form or nature to the totem spirit of his tribe or cult. In order to become a shaman, a spirit magician must first locate his fetch in a dangerous initiation ritual. Such spirit-quests involve the re-enactment of his cult's mythic foundation to locate his guardian and culminate in a dangerous battle against the traditional enemy of his practice.
The fetch aids the shaman, protecting and guiding him in the spirit world. It is in every way his spirit brother.
The benefits of a fetch are:
• The shaman can see spirits, souls and magical auras without needing to enter a trance
• The shaman can transfer the Magic Points of the fetch to replenish his own
• The fetch can discorporate the soul of a mundane living being, who may resist with an opposed roll of his Persistence against the spirit’s Discorporation skill
• The fetch can possess the shaman’s body whilst he is discorporate, protecting it
• The fetch can substitute itself instead of the Shaman in spirit combat (if in the same location)
• The fetch and shaman are in permanent mental contact, and are aware of each other's senses
• The shaman may invoke any power or ability his fetch knows, and likewise the fetch may cast any Common Magic the shaman knows.
• The bond between shaman and fetch is not vulnerable to magical dismissal
The detriments of a fetch are:
• The fetch may influence the personality of the shaman depending on its totem nature (i.e. a bear spirit fetch may cause the shaman to become soporific during the winter)
• The fetch may draw upon the Magic Points of the shaman in times of dire need
• The fetch will abandon the shaman if he betrays the teachings of his shamanic tradition
A fetch starts with 200 skill points to be assigned to its skills. Fetches can grow in experience just as the shaman does. If desired, a shaman can transfer any or all of his skill improvement rolls to his fetch instead.
A fetch is, essentially, the same as any other spirit but it interacts with the shaman differently and can be developed in the same way as a player character. A fetch is bit like a familiar or a retainer. Its bonded to the shaman and can augment that shaman's capabilities, but the shaman has certain obligations towards it, or the bond becomes compromised.
Are shamans too powerful? Their power level is there to balance this form of higher magic against the power of Divine and Sorcery. A shaman can be devastating if he calls upon his fetch or allied/bound spirits to destroy his foes, but I think you also need to look carefully at the cultural background of the shaman too. A shaman who comes from a culture that venerates nature is less likely to call upon the spirits to kill than, say, a broo shaman who is allied with disease spirits. This, to me, should always be the first port of call when considering a shaman. What does he consider to be taboo? What have his ancestors taught him? What is the example set culturally by his tribe? Would his fetch obey a command to discorporate and savage an enemy?
You'll find an example of how subtle this can be in 'Pavis Rises'. Some of the elves of the Garden there have access to powerful nature spirits but its made clear that any attacks they make using their spirits are not hurtful but designed to inconvenience and embarrass.
I do agree that spirit magic is a very deep, complex magical form that hasn't been necessarily easy to discuss in the constraints of the rulebook. Pete and I have discussed producing a spirit magic clarification article for S&P and this will happen at some stage, although much is dependent on Pete's writing schedule. But the arguments aren't lost on us and we're always happy to offer clarification and examples whenever we can.
