Spirits

are the souls of the deceased that reside in the pure land. They possess a unique type of chakra known as, which results from their unbound state in the afterlife. Due to this extremely potent chakra which they possess, persons from the Land of the Night invented methodologies of summoning and subjugating them, dubbing the process "fujutsu". This art has been decried by some in the past, as it was seen as the desecration of the sanctity of the deceased. Nonetheless, the practice of fujutsu continues into the present day, due to the great powers that can be derived from summoning spirits.

Overview
Once a person's body can no longer support their life, the soul of the person ascends into the pure land, where it resides. Once in the pure land, the soul becomes an ethereal entity which is endowed with a very powerful type of chakra. This chakra is the reason the spirit is able to sustain itself as a sentient being, as without it, it would simply fade into nothingness. The spirit is still bound to the real world by their emotional attachments, however, this being the reason why they are able to be invoked from those who are bound to the impure land. Were the spirit to be returned to a physical body, this chakra would simply dissipate into the surroundings as wasted energy, as it would no longer be needed to sustain it. Once the spirit has been summoned to the physical world, it is typically bound to the will of its summoner, and forced to give its chakra to them in order for them to be able to use their power for various techniques. When a spirit is summoned, they appear as flickering apparitions for a brief moment, before transferring their power to their summoner. During this transferal, the eyes of the summoner glow brightly with the color of the summoned spirit. This is due to the fact that the chakra is so energetic, the light emitted from it illuminates the entire summoner's body. However, the eyes are the only translucent part of the body, and hence allow light to escape, thus why light seems to come from them.

Types of Spirit
There are six known types of spirits, called the, named after the emotions which are thought to constitute the fundamental principles of human nature. A spirit falls into one of these classifications based on the personality and traits they held while they were alive. In addition, a fusha's compatibility with a specific type of spirit is contingent on his dominant emotions. The type of spirit which he has an affinity is accordingly reflected in his usual state of emotions.

These are the six types of spirits:
 * , which are typically surrounded by a crimson aura, are spirits whose predominant emotion was anger when they were alive. This is the most common type of spirit to be summoned.
 * , which are typically surrounded by a deep blue aura, are spirits whose predominant emotion was love when they were alive.
 * , which are typically surrounded by a light blue aura, are spirits whose predominant emotion was happiness when they were alive.
 * , which are typically surrounded by a green aura, are spirits who were predominantly concerned with the pursuit of their own pleasure when they were alive, and were thus selfish. This is the rarest type of spirit to be summoned.
 * , which are typically surrounded by a mauve aura, are spirits whose predominant emotion was grief when they were alive.
 * , which are typically surrounded by a yellow aura, are spirits whose predominant emotion was hatred when they were alive.