Muslim teachings are that the soul never dies and will never die even if the person associated with that soul ends up in hell.
According to Muslim teachings, each person has their own soul. This is a departure from Hindu teachings were different bodies share the same soul during different times. Back to Muslim teachings, each new born person is given a soul which continues to live after they pave passed on. At some point in the future, everyone will be resurrected with their souls restored to them. There is a final judgment where some are awarded heaven while some are sentenced to hell. Recipient to both of these abodes will remain there along with their souls.
Where/what is the reservoir of souls? Is there a one to one match up? If so, what is the state of the souls that are waiting for bodies?