Momiji ponders, turning back to look at Momo for a moment, before replying. "It's actually much more rare for a human to be incapable of it. Though it's also rare for them to be extremely proficient in it. The most basic form is pure spiritual energy manifest, much like what I and Momo use. Humans tend to have a smaller spiritual presence, so in turn have little ability in it. Though, the absence of the ability obviously is not indicative of no spirit. Though, there is also manifestation of physical energy, and magic, and many others."