It could be an image that could be used to allow them to send their Life Energy that way, or it could just as easily be a word or a set of words.
Those words could trigger a mental image within their minds, resulting in their Life Energy contributing toward bringing life and form to that Spirit or Evil Spirit.
If a guardian or pet were to be created in the image of something specific, then that image needed to be present in the minds of most of the humans who would contribute to its birth.
Once it took on its form, there was no going back.
It could not be changed once it was born and took on its form in its much smaller and weaker newborn state.
It was the same if the negative Life Energy that was sent toward it contributed more to its birth.
If it was born as an Evil Spirit, then it was not something that could be changed.
In most cases, the Evil Spirit would be eliminated on the spot to prevent future problems.
