Combat boot. Combat boots are military boots designed to be worn by soldiers during combat or combat training, as opposed to during parades and other ceremonial duties. Modern combat boots are designed to provide a combination of grip, ankle stability, and foot protection suitable for a rugged environment.
In our earthly life, a lost soul is someone who has no direction in their life, no apparent purpose. They have many acquaintances but few friends. Those who do know this person think them a little strange, or socially awkward. Perhaps some of them are psychopaths, people who lack empathy.
Soul Reapers are souls that have supernatural powers. As such, their bodies are composed of Spiritrons (spirit particles) instead of atoms. This means that just like most other types of spirits, they can only be seen by other spiritually aware entities, which excludes most humans.