Honestly in simplest terms it's just an advanced application of the basic principle behind every single Sage Transformation technique and the clan itself in general. This principle being the ability to draw in and use ambient Natural Energy to go through rudimentary transformations. This works on that principle, drawing in additional Natural Energy more than the user naturally does to go through those transformations I had a similar idea a while back without the additional layer of skin where the user would go through a process similar to the Complete Sage Transformation without needing to undergo the full transformation entering a heightened state of awareness. However your technique does this by creating an additional layer of flesh that draws in more Natural Energy than the users own epidermis. My personal opinion is that it's like adding another layer to the epidermis though you can correct me if I'm wrong but usually the body has three layers of skin. These layers are called the epidermis, the upper most layer of skin, the dermis, the second most layer of skin and finally the hypodermis the lowest layer of skin. The epidermis is the outer most layer of the three layers that make up the skin. This skin layer provides a barrier to infection from environmental pathogens and regulates the amount of water released from the body into the atmosphere through transepidermal water loss. The outermost part of the epidermis is composed of stratified layers of flattened cells that overlies a basal layer composed of columnar cells arranged perpendicularly. The rows of cells develop from the stem cells in the basal layer. ENaCs are found to be expressed in all layers of the epidermis. he dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided into two layers, the superficial area adjacent to the epidermis called the papillary region and a deep thicker area known as the reticular dermis. The dermis is tightly connected to the epidermis through a basement membrane. Structural components of the dermis are collagen, elastic fibers, and extrafibrillar matrix. The hypodermis houses the blood vessels and subcutaneous tissue such as fat, connective tissue and even the follicles of deep rooted hair. It's more the area that houses these substance than a direct layer of skin like the other two.
So by doing this it temporarily magnifies the users natural resistance to genjutsu, I believe if you wanted to you could expand this by editing the technique to include any mind probing techniques as well as if you create it so that the pores stop the skin and flesh itself from absorbing gaseous substances you could gain a temporary immunity to gas based poisons though that would take an update to accomplish. This is done by creating a continual influx of Natural Energy that each turn spikes the users usual chakra flow more than their passive ability to draw in Natural Energy does each turn creating a substantial burst of inward flowing Natural Energy which is forced to crudely balance with the users own chakra as Sage Transformation users cannot be turned to stone. So, it boosts the usual immunity from C-rank genjutsu up to everything below MS. Due to the wording this means everything E through Forbidden Rank including Elemental genjutsu and even Kurama clan genjutsu which allows for a way to passively defend from genjutsu. A good example of something similar would be my Weapon X medicine which creates a large influx of Natural Energy breaking genjutsu in a similar matter while healing the user. The reason I wanted this technique was because it gives me an additional way to combat genjutsu in either a quick or passive manner, I hate genjutsu, always have probably always will. I don't like using it and I don't like it being used upon me I tend to only use it when I feel like it can be used as a joke. That's not to say I don't have decent genjutsu techniques, I have one given to me by Leaf that restricts the opponent down to B rank techniques making it impossible to break through most chakra surge based techniques forcing them to rely on pain. Anyway if you've gotten this far, good on you I just wrote this out because I wanted to see how long you'd read before being like "eh **** this shit he's just bullshitting me."
Anyway. Here.
GL;HF.
