The Limitations and Benefits of Shape Shifting

Both the nephilim and the seraphim have the ability to shift and manipulate shapes. The nehpilim have a reputation for using the shifting for trickery. This is why Noah and his family can't find Sandy when he is captured. The nephilim have made his tent invisible. Both groups also shift into animal shapes. This is helpful to them because it allows them to blend in with scenery, and it also allows them to keep an eye on what's happening around them. For example, when Yalith goes into the desert, it's easier and less conspicuous to follow her as an animal than as an unusually tall man. Another benefit of shape shifting is practicality. A seraphim turns into a camel to help take Dennys across the Dennys.

On the negative side, shape shifting takes a lot of energy so it can't be done...