Atavistic Flame which is also called The Human Principle which is a connection to the human soul. This principle has a number of effects which are Spiritual Recoil, Healing, and Causing Physical Harm. It takes form as a yellow flame with an orange center when it causes harm and burns the user’s actual soul to perform these feats. This style is connected to spirit, spirituality and spiritual energy but this doesn’t make it Yin Release.
Now this style is something that only humans can use. Also the style is chakraless and is neutral to everything besides Suen, Utu, and Anutu. With it being stronger to things like Suen, Utu, and Anutu it can fight against the Divinity enemies in the Ninja World. This is also how Marzan creates the God Slaying Tools in his forge.
Against Suen, Utu, and Anutu each ranking of this style has an advantage over each release. The starter rank is Initiate have a 20 chakra advantage and Masters and Grandmasters 40.
Now this style is a Mode but some of its techniques don’t require the Mode to be activated. The Mode itself is split between its three ranks(Initiate, Masters, and Grandmasters). The Mode is best used the lower your health goes because just like how Sage Mode is best used at the beginning of a fight and gets a large pool to use its techniques this Mode uses the health you have lost to create a pool to use its techniques in. The Mode is broken down into stages which are Hollow Flame(Initiate), Blaze(Master), and Inferno(Grandmaster).
Example: You are a Jounin and have 160 health. You have lost 120 leaving 40 health remaining. You can use that 120 as a pool for the Mode.
Now when the user uses an Atavistic Flame technique it does cause self inflicting spiritual damage but over time it slowly heals the user’s damage they received. Besides self inflicting themselves the user can also use the flames to primarily heal themselves from spiritual damage they receive with a certain technique of this style.
Just like Suen, Utu, and Anutu it can't be sealed, drained, or absorbed. It also can’t even be replicated or stolen. So things like Fuuinjutsu are useless, just like SNT.
This style doesn’t require any hand seals but it isn't as fast as Taijutsu. It also falls under the Fire Release speed rules for ranged usage. Also it can’t be combined with chakra techniques besides somethings like Chakra Enhanced Strength(still don’t understand this part on how it can’t be combined with Chakra techniques but can be combined with Chakra Enhanced Strength).