In tA "soul" can be considered as a composite of multiple aspects of one's own self. There's the soul-propper, the spirit, the anima--or animating force, the gnosis, the shadow and so on. Each of these can be reconfigured as needed, to create what the myriad cultures of Earth consider to fit their definition of "soul."
The soul proper is one's morality, and the source of one's free will. It is one's values, one's passions and fears, the key to fulfilling one's potential as a living, sapient being. Someone without a soul is an automaton, lacking the ability to choose their own paths and make their own impact on the world, to be a hero or a villain. That's why trading away a soul can be so powerful--your trading away your ability to affect your life and the lives of others.
The spirit is more the concept of who and what you are. It is your self-image. It holds your name, your titles, your relationships--everything that connects you to the rest of the world. Ghosts are formed when a departed being chooses to latch onto their spirit and make that their defining element, fettering them to the world of living through tasks yet unfulfilled and relationships left unresolved. While a person can only ever have one soul, they can have multiple spirits. A werewolf has both the spirit of man and wolf, while a hero may bond with the spirit of a long-departed champion.
One's anima is their animating force. Also called elan vital, ruh, qi, ka, mana, prana, pneuma, ruach, vril, or the Odin force, it infuses all living things, giving them the metaphysical energy they need to act. It flows in a continuous cycle, and every living thing, from the lowest bacteria to the greatest dragon and the largest whale are constantly taking in new anima, and expelling the used anima naturally. The very act of living draws in anima, from producing or consuming food, to reacting to stimuli, to growing, to reproducing. Anima is also the energy of magic and is channelled by mages, psychics and supernatural creatures to work their fantastic abilities.
The gnosis is one's understanding and knowledge of the universe. It goes beyond mere knowledge--an astrophysicist might have weak gnosis while the janitor who cleans their office every night might be possessed of an incredible one. Gnosis represents one's connection to the fundamental forces of creation, the ability to see how everything is interconnected in complex metaphysical webs and patterns. With great gnosis, one can tap into these fundamental forces, and transcend the barriers of one's physical body.
The shadow represents one's darker aspect. It is the part of one's self where the light of a soul doesn't reach. It isn't evil, so much as amoral, utterly selfish and devoted to one's own self-interests at the expense of all other rational thought. While in most people, the shadow is weak, in those consumed by evil, the shadow can grow to dominate a person. Certain supernaturals also have to contend with a stronger shadow. To horrors, the shadow is "the beast," the inner primordial monster who incarnates their fears. To vampires, it is "the hunger," the burning need to consume the anima of the living, to indulge one's nature as a predator.
Fitting these aspects together can help to create the complete picture of a person--and this is not including other parts such as one's mind and body that some cultures also consider to be part of a soul. Humans are complex creatures and exist on multiple levels--including metaphysical ones. Trying to understand how we work can take ages of scholarship.