The most advanced form of bringing life to a dead soul,  involves not only
raising the soul from the dead, but also restoring the body. The new body is
fresh and whole, but will take time to meld to the soul which returns from the
dead  virtually intact. If the original body was weak, care must be taken, or
the strain of changing bodies may be too much, since much of the soul's
strength does reside in the body itself.