(Author’s Note)

A Rough Reference section (updated as of ch 99). These are all explained throughout the story, but I’m putting it here for additional clarity.

=== Souls ===

Soul force is a higher dimensional energy that gathers around a new life and spontaneously forms a soul upon the early stages of consciousness.

Soul Tier 1 - Mortal, regular humans fit in this category.

Soul Tier 2 - Mortal, but superhuman in one or two aspects. Lowest possible tier for immortality to be available. Enlightened individuals like Iroh and Bumi fit into this category. Raava and Vaatu are both peak Soul Tier 2.

Soul Tier 3 - Partial immortality. There is no human in Avatar that reached this level. Only beings like the Tree of Time and the World Tree fit into this category.

Soul Tier is increased via spiritual enlightenment or soul force condensation. The strength of a soul is determined by the individual’s Soul Tier, Soul Force accumulation, and Willpower.

Almost all mortals go without ever increasing their Soul Tier.

Soul Tier is different from a bender’s chi capacity, but it has an effect on it. For example, an individual with a Tier 1 soul can still assassinate or defeat someone with a Tier 2 soul. The difficulty of doing so would be very high without powerful auxiliary abilities.

=== Chakras ===

Chakras only apply to the Avatar Record. All humans in the Avatar World have a Mortal Shell (body) and a Spiritual Body (consciousness). The Mortal Shell corresponds to the Mortal Realm and the Spiritual Body corresponds to the Spirit Realm. Chakras are the wellsprings of chi and refer to places on the Spiritual Body where chi can be gathered. They are also the connection between the Mortal Shell and the Spiritual Body. When a bender manipulates chi, their Spiritual Body interfaces through its chakras with the Mortal Body in order to provide the Mortal Body with chi to manipulate.

In mythology, the spiritual body represents the ultimate potential of a human being where all chakra points are fully unblocked. Each time a human with blocked chakras deepens their understanding of the world around them and themselves, one or more of their chakra points become unblocked, which increases the chi they have access to as well as their connection with the Spirit Realm.

Each chakra or chakra point can be further “unblocked” by gaining a deeper understanding of the aspect of personality that each chakra point represents.

Crown Chakra (Top of the Head) - Represents Knowledge and Consciousness

Third Eye Chakra (Forehead) - Represents Intuition and Lucidity

Throat Chakra (Throat) - Represents Communication and Creativity

Heart Chakra (Heart) - Represents Love and Sincerity

Solar Plexus Chakra (Stomach) - Represents Strength and Determination

Sacral Chakra (Genitals) - Represents Sensuality and Pleasure

Root Chakra (Feet) - Represents Energy and Stability