So this is just going to go over the various concepts of the Forsaken By God verse (Forsaken Verse).
The Four Planes
Reality in the Forsaken verse is divided into 4 'planes' (these are NOT equivalent to dimensions). They are referred to in order "height", or rarely "depth" with the highest also being the deepest, and the lowest being the shallowest. Every being in the Forsaken verse exists on at least 2 of these planes. These planes are:
Assiah, the physical plane. This plane is inhabited by all physical objects and forces in the multiverse. Matter, light, gravity and time all exist on Assiah. This plane is inhabited by the body. Magic that controls fundamental forces, physics, matter, space and time, and other similar things is done by using magic on the Assiah, and is commonly referred to as first planar magic
Yetzirah, the mental plane. This plane is inhabited by the Psyche (mind), and is inhabited by feelings, dreams, beliefs, fears, hopes, etc. Magic on this plane is commonly used for mind control, mental illusion creation, projections, empathetic manipulation, etc. A person's Faith (see Magic) is linked to the strength of their Psyche on the mental plane. Magic used on this plane is referred to as second planar magic.
Ber'iah, the spiritual plane. This plane is inhabited by the soul of nearly all living beings in the Forsaken verse. Magic on this plane is called 3rd planar magic, and can be used to destroy, create and manipulate souls. A person's Anima (see Magic) is linked to the strenght of their soul on Ber'iah. It is the hardest of the natural three planar magics to wield and the most powerful of the magics that normal humans are capable of.
Atzulith, the conceptual plane. It is simultaneously the deepest and the highest of the planes. This plane is the foundation of all reality in the Forsaken verse, where the ideas that shape the fundamental structures of reality exist. All magic wielders can affect themselves within the conceptual plane via Veritas Et Mendacium (see below), but it is impossible for all but the most powerful beings to affect anything else on the conceptual plane. However, certain abilities such as Tetragrammaton's Ego Potest Creare Mundum Melius and the Superiadeum's Mundus Est Mea are capable of re-writing or erasing the concepts that exist in Atziluth, allowing them to control the near-totality of the Forsaken verse's reality.
Additionally, by controlling higher/deeper planes, one can also to a degree control the lower/shallower planes. E.g. Control the mind of someone and you control the body, control the soul of someone and you control their mind, control the concept of something and you control everything about them.
Finally, the planes, like magic (see below), are absolutes. Even abilities such as Tetragrammaton's Ego Potest Creare Mundum Melius and the Superiadeum's Mundus Est Mea are unable to create, alter or destroy the planes themselves, even conceptually, although like all magic they are capable of affecting things on the planes.
Manna in the Forsaken verse is described as the 'key' that opens the lock for humans to access their magic. The act of using magic is made of multiple steps, the first being known as the "Opening", where the person uses the manna as the door to access their innate power. It is separated into two types, demonic and seraphic. This only refers to the origin of the magic, with demonic magic coming from hell and seraphic magic coming from heaven, as a wielder of seraphic magic and a wielder of demonic magic can do much the same thing. However, there are certain things that will only react to magic "Opened" by specific Manna types, such as the Gates of Heaven only opening in response to magic "Opened' by Seraphic Manna.
However, the body can be overwhelmed with manna. Although a strong Anima and Faith can increase a body's tolerance and manna capacity, once a person reaches this limit, using either Seraphic or Demonic manna, their body undergoes painful and potential lethal changes. Overuse of Demonic manna will at best kill a person instantly and at worse transform them into a terrible demon, twisting their mind and body. Overuse of Seraphic manna has never been seen in series, but from the effects seen when Hope Elizabeth approached her limit, it involves burning. Lots and lots of burning.
Magic in the Forsaken Verse is more than the simple magic of Fairy Tail or Harry Potter. It is a primal force from before creation that can govern everything in existence and exists within everything in the verse on each of the four planes. It is a constant throughout all existence, an absolute that can never be changed - the way to access the magic may change, but there will always be magic. It can be used for a variety of purposes, with the abilities and potency of the magic being dependent on the wielder's Faith (a non religious term referring to the strength of their belief in something), and Anima (the innate strength of their soul). Magic wielders are thus essentially capable of anything they believe they are capable of. Magic wielders (everyone) also enjoy several passive abilities granted by their magic, such as Shields and Veritas Et Mendacium.
How much magic a person can use is dependent on how strong their soul is. While humans have far weaker bodies than the vast majority of angels and demons, the strength of their souls is vastly superior, allowing even the weakest of humans to battle with demons capable of tanking direct nukes when empowered by their magic. Some humans have even stronger souls, that allow them to reach Island level or higher. Additionally, it is possible to strengthen one's soul through various methods, the normal way being truly "living", testing the boundaries and limitations of one's self. Basically, if it causes strong emotions, it's strengthening the soul.
Magic in the Forsaken Verse can be used for almost any purpose imaginable. By acting on the 1st (physical plane), all magic users are capable of strengthening their bodies to become stronger and faster, elemental manipulation, hellfire manipulation and matter manipulation, More advanced users are capable of molecular manipulation, forced regeneration (generally Low-Mid, though expert physical users are capable of Mid regen), biological manipulation, creation and physics manipulation. Almost any conceivable ability that acts on the physical world can be gained by manipulating objects and forces on the 1st plane. This is the same for the 2nd and 3rd planes, with soul destruction and mental manipulation being the most commonly used forms, though more advanced users are also capable of soul and mind creation, merging and absorption (extremely rare), and Low-Godly regen (from the soul or mind). However, the level of the ability is dependent on the power of the magic user. Also, the only way (apart from certain Supreme Truths - see below) to use magic on the Fourth Plane is Vertias Et Mendacium (see below).
Focuses are objects used by human magic users to direct and control their magic. Due to their lack of experience with magic, humans must use objects with special significance and meaning to them in order to direct their magic. For example, Luther Francis's focus is a small silver crucifix necklace which he uses as the Focus of his light based magic. It must be noted that humans can still use magic even without a focus, it is simply less controlled or precise and more instinctual, and even this weakness can be removed with enough practice.
Veritas Et Mendacium
Veritas Et Mendacium (Truth and Lies) is an ability enjoyed by all magic users. Passively, all concepts the user believes in are warped into "Truth" within the wielder, while all concepts they do not believe in are warped into "Lies" within them. This results in the magic wielder being extremely resistant to the destruction of concepts they believe in, and extremely resistant to the application of concepts they do not believe in. For example, attempting to conceptually erase any magic user with a sense of self would be difficult, as the concept of "myself" is something they believe in, while attempting to apply the concept of Death to any living magic user would be difficult as they believe themselves being dead as "Lies". Most of the time, this effect is limited to within the user. However, some extremely powerful beings, such as Tetragrammaton, Satan, and EoS Adam and Hope, are powerful enough that the effects of this ability can spread outside their bodies, enforcing or negating concepts they believe or disbelieve within a certain distance of them.
Magic passively gives the wielder several "Shields" on the physical, mental and spiritual planes of reality, giving them increased durability and resistance to soul and mental manipulation. Even the weakest human has the Anima, and thus magic, capable of blocking nuclear weapons, placing them as between Town (7-C) and possibly City Level (7-B). Shields also block the effects of unwanted external magic being used on the physical body, granting resistance to directly having their matter manipulated, death manipulated, space/time manipulated, etc. It should be noted that Shields are not the only defense people have - they simply add to the person's physical durability and resistances to soul/mind hax. Shields are damaged from repeated attacks - however, they also regenerate extremely quickly, being back to full strength within minutes of being damaged. Although (as established in the next section) people's magical capacity is evenly divided between different applications, a person can draw in more manna in order to increase their magical power and defenses. However, as established in the Manna section, overdrawing manna can result in being overwhelmed by the manna and instantly dying - or worse.
Essentially the way to hurt a magic user is to simply overpower their shields with powerful successive attacks to any of the planes, thus breaking the shields and allowing you to act directly on their physical body, mind, or soul.
Abnormals and Enlightened
A person's magic is generally evenly split into 7 parts, one offensive and one defensive portion for use on each of the three planes, and one for powering Veritas Et Mendacium . Because of this, a person's resistance to soul and mind manipulation is generally equivalent to their physical durability, and their resistance to conceptual manipulation. Likewise, the strength of their soul and mental manipulation is generally equivalent to their physical destructive capacity with magic. So a non-Abnormal person who can resist the mental manipulation of another non-Abnormal who can destroy a continent is themselves capable of destroying a continent. However, there are some rare exceptions to the rules, known as Abnormals, whose physical, mental, and spiritual strengths and resistances can vary wildly, and Enlightened, beings who through intense training can freely apportion their magical power. This also means that if there are two people with the same magic levels, if one of them has all of their magic apportioned to physical offensive capability, they are seven times physically stronger than the other person, though their durability and resistances are completely natural. This makes Enlightened beings a force to be feared, as they are capable of changing the levels of their strength and defense to suit the situation.
Veritas Maximus (Supreme Truth), is the ultimate magic of Faith and Anima. Upon activation, it uses all magic the wielder has to power it, removing all passive effects granted (including Shields and Veritas Et Mendacium). In exchange, it enforces the user's deepest belief upon reality. For example, Legion believing "There is nothing but pain", means his VM causes incredible pain to everyone. Although the ultimate potency of this power is dependent on the user's Anima, this power can completely bypasses the Shields of others, effectively acting as if on a non-magic user.
It should be noted that while this power exists within every magic wielder, it is rare for a being's deepest belief to be useful in some fashion. Many 'deepest' beliefs are things that are already reality, while other deepest beliefs would be detrimental to the user should they be enforced on reality. Additionally, as the use of Veritas Maximus uses all power, including that of Shields and Veritas Et Mendacium and thus removing all defenses for the duration of tis use, many find it is not worth the cost to enforce their belief.
Demons and Angels
Demons and Angels (classified as originating from either Hell or Heaven respectively) are simply beings from other universes lin the Forsaken verse. However, they are made of different matter types than from humans on Mundus (think Cthulu being made from "something that only qualifies as matter in the most basic sense"), and thus are largely resistant to hax such as matter manipulation. Their worlds also operate on different laws of physics that the human world, and both angels and demons carry these physics with them internally. This makes them extremely resistant to physics manipulation.