Hosts are humans (or other individual organisms) who have had their body and mind taken over by a Soul. Skippers are Souls who do not complete their hosts life-term before moving on to a new host, possibly on a new planet. Doing this without a valid reason (such as the mental health of the Soul) is viewed as wasteful and goes against general Soul philosophy. A Calling is equivelent, but more intensely viewed, to a job which the Soul feels an affinity towards (see below).