Before you start, take note of these stats: Mental Fortitude, Belief and Strength. They are important.

For easier remembrance:

Mental Fortitude: Protects a Tasker's psyche and enables them to manifest a weapon that can harm souls in the Soul realm and Realm of Realms.

Belief: This stat is a Tasker's defense mechanism. The higher a Tasker's belief stat, the stronger he is against the weapon that has been created from another Tasker's mental fortitude.

Strength: As a novice or intermediate Tasker, this stat does nothing but make the body of the Leaser stronger in a task realm.

-This stat only becomes very important when a Tasker reaches the Advanced level because then, Leasers would no longer be needed to enter a Task realm and Soul energy would be gotten from x2 of the amount of strength cultivated in a task realm.

I.e: If, at the end of an Advanced level Task realm, a Tasker earns 1,000 strength points, this would equate to 2x1000= 2,000 Soul energy.

More info about the above three is given in the glossary.

A:

ADVANCED TASKER:

-The third level of being a Tasker. Need 1,000,000 Exp points to achieve. The amount of EXP points gained after each task is +200,000. This means that if a Tasker's first task as an Advanced Tasker earns 100,000 Exp points then their second task as an Advanced Tasker would earn +200,0000 Exp points which makes a total of 300,000 Exp points and so on. i.e 500,000, 700,000, etc.

*The test task taken before every level upgrade does not count.

-At the Advance level, a Tasker no longer needs a leaser in order to be able to seamlessly merge with a task realm. Rather, they get to choose which task realm they could go too from Genesis and then automatically, their able to manifest a physical body and enter that task realm.

-They are able to seamlessly merge with the Tasker realm without a leaser be ause the task realm itself would automatically create an identity/role for them and this identity is what they get to follow until they left the task realm.

-As soon as an identity is created by the task realm, memories of the role that the Tasker had been assigned would automatically appear in the minds of the inhabitants of a Task realm and once the job is done and the Tasker leaves the realm, all memories of that identity would automatically disappear from 5he minds of that inhabitant.

B:

BELIEF:

(Going to be spoiling here but it's nothing major.)

-Belief points are gotten through any form of worship or gratitude that could be passed down to a large number of people. If a Tasker happens to leave a legacy or a mark behind in a realm and this legacy is used by consequent generations, this could gather belief points for the Tasker.

-The special thing about Belief is that it is a Tasker's defense against an attack from a fellow soul. (See M. mental fortitude for how a soul could attack another soul)

BLOCKERS:

-This is a talisman like object that can only be found in the black market of the Soul realm. This object is generally banned because it enables a Tasker to hide their energy from their systems -making it impossible for their systems to locate them.

-This is a vile object used by Taskers who either want their systems to be obliterated by the Guardians for breaking the rules or just because they want to selfishly changed systems.

-It is a system's misfortune to have a blocker used on them.

F:

FIRST GENERATION SYSTEMS: These are Systems that were not made/selected by the Soul Realm. They total just 10 and had been created from the residue of Chaos when the Realm of Realms was birthed from The Source.

-Just like the Realm of Realms, it is impossible to kill/destroy/obliterate a First generation system but they have limitations to counter their strength. (Can't give more info because I don't want to spoil. Sorry)

G:

GENESIS:

The void of creation where each Task realm is born. (Check out T. 'The Source' for origin). It's appearance is a huge dark void with millions of tiny globes floating about. These globes are the Task realms.

-Genesis stands in between The Realm of Realms and The Anti-Realm of Realms. It is the balance that keeps both sides functional.

H:

HUNTERS:

-These are Ultra level Taskers who have ascended into The Realm of Realms and gone through a special test. 

*Note: ultra level Taskers who do not go through this test cannot become Hunters. They only end up living their lives peacefully and choosing select tasks to take on when they need to.

-Hunters are like the Police force of the souls and hold the power to obliterate a soul into nonexistence. Enforcing the laws and maintaining order in both The Realm of Realms and the Soul realm was their duty.

-Their appearnce is: Covered in black from head to toe -not a single inch of skin to be seen- and a mask over their faces.

-Their choice of weapons varied depending on each Hunter but in all, their weapons are gotten from harnessing their mental fortitude and manifesting a soul weapon that works effectively on souls.

*Note: All souls with high mental fortitude can do this.

I:

INTERMEDIATE TASKER:

-The second level of being a Tasker. Need 100,000 Exp points to achieve. The amount of EXP points gained after each task is +100,000. This means that if a Tasker's first task as an Intermediate Tasker earns 100,000 Exp points then their second task as an intermediate Tasker would earn +100,0000 Exp points which makes a total of 200,000 Exp points and so on. i.e 300,000, 400,000, etc

-At this point, it is possible for a Tasker To personally meet the Leasers and negotiate the terms of their counterattack contract.

-If a Tasker is dissatisfied with the first leaser that shows up in their System Space, they are free to reject the leaser and move to the next one. The catch is... They are unable to reject counterattacking for the next leaser that shows up. Even if the leaser is a bad person.

C:

COUNTERATTACK: This basically means a Tasker getting revenge/justice for a Leaser in exchange for using their bodies to enter the Task realm.

M:

MENTAL FORTITUDE:

-This is a stat that determines how strong a Tasker's psyche is. A low mental fortitude could lead to a Tasker losing their mind.

-Mental Fortitude is special because it is only through a high mental fortitude that a Tasker can manifest a soul weapon. (Soul weapons are the only thing that can harm a fellow soul)

N:

Novice Tasker:

-The beginner level of being a Tasker.

ORIGIN REALM:

This refers to the world of all Taskers/Reapers/Tasker's Systems before they died and became Taskers/Reapers/Tasker's Systems. (I specifically used Tasker's Systems here because the Reaper's Systems pq are created differently. See T. Anti-Realm of Realms for more info.)

PHYSICAL BODY:

This refers to the bodies of Advanced Taskers when they enter a task realm. This simply means they get to use the same physical bodies they had in their origin realms. Their soul automatically turns into a real solid body with all the bodily functions as soon as they enter the realm.

REAPERS:

-Reapers are to the Anti-Realm of Realms what the Taskers are to the Realm of Realms -although they are significantly fewer in number (Reaper to Tasker ratio is 1000:1). Reapers are people who had committed major crimes in their origin realm and are offered a contract at the point of their deaths.

-The initial period of becoming a Reaper involves them absorbing chaos energy in their System void instead of taking on tasks. This could take anywhere between a 10 to a 100 years as any sense of time is warped outside of the Task realms.

-Once the new Reaper had absorbed enough, their strength would immediately become on par with an Advanced level Tasker. This is the reason only Advanced level Taskers and above are able to encounter them in a Task realm.

*Note: The lives of the Reapers in the Anti-Realm of Realms is based on survival of the fittest. Once they are sent out of their System void, whether they live or die would depend on their own strength so in order to survive, they need as much chaos energy as they could get from increasing a Special one's luck and ripping the strands of a Task realms existence. 

-This why they have to constantly go into Task realms. They do not get punished for failing a Task realm but in order to survive in their hell zone, they need as much chaos energy as they could get.

-Due to the nature of the Reapers, they have one limitation. They aren't allowed to arbitrarily kill inhabitants of a task realm and if there was a valid reason to do so, they could not be found out by the inhabitants of the task realm.

*Note: Whether something is considered a valid reason or not is dependent on the Task realm itself so this reason has made Reapers cautious about killing in a Task realm as breaking the valid reason rule could lead to obliteration.

S:

STRENGTH STAT:

This stat determines the physical capacity of a Tasker whilst in a task realm and in a task realm alone. This means that the Strength stat is ineffective against souls in the Soul realm and the Realm of Realms.

*Note: The [Strongest Martial Arts] can only be used whilst in a task realm where martial arts matters. Martial arts only strengthens the physical bodies and not the soul. This is why, although He Yuan diligently practices the [Strongest Martial Arts] in every task realm, he doesn't practice it when he returns to the System Space as it has no effect on his soul.

-The only way the [Strongest Martial Arts] would have an effect is when he becomes an Advanced Tasker and manifests a physical body in the task realm. I.e, He goes into the Task realm with his own body, practices the [Strongest Martial arts] and when he returns, his soul energy would be strengthened.

-The reason for this is: Since a leaser is no longer needed, his soul energy would have to come from somewhere else and that is his own absorbing of qi/energy in the Task realms.

 (Although he still will not be able to practice martial arts in the System space)

SOUL ENERGY:

The density/Thickness of a Tasker's) System's Soul is dependent on this stat. A high Soul energy automatically means the manifestation of a Soul body in the Soul realm or Realm of Realms (Basically outside of the Task realms).

-A high Soul energy is what makes it appear as if the Souls in the Soul realm have real bodies. A high Soul energy also means that a Soul is able to unlock all six senses (that means they can now taste, feel, smell, etc without needing to use products from the System Marketplace to achieve this).

*Note: All systems automatically have high Soul energy (i.e Manifest Soul bodies) the second they become systems unlike Taskers who have to work for it from scratch.

SYSTEMS:

These are people who had committed great crimes in their origin realms. Normally, these kind of people are selected to become Reapers in The Anti-Realm of Realms but in order to cut down on the number of Reapers, the Upper echelons in The Realm of Realms came up with the idea of snatching them over first.

Because they would end up becoming scourges to the Taskers anyways, they are heavy limitations placed on every system. These are;

Interfering with the Task realm = Punishment.

Not staying within reasonable distance of their Hosts during a task realm = Punishment.

Using more than the stipulated amount of energy in a Task realm= Punishment.

Losing the connection with their hosts whilst in the Soul realm= Obliteration.

The death of their hosts -whether or not the systems are present= Obliteration.

Killing the Special one of a Task realm= Obliteration.

-Their job is to give mild suggestions to their hosts and mild assistance that has been approved by the Upper echelons because it is believed that since these systems were meant to be Reapers, whatever interference or strong suggestions they gave would only lead to the complete break down of a Task realm.

*Note: Systems are nothing special in the Soul realm. Their post was only created to reduce the amount of Reapers the Taskers had to deal with. This is why they have so much limitations and no importance is placed on their lives.

-According to the Upper echelons, becoming a System is also punishment for the crimes these souls had committed in their origin realm so they feel justified in placing strong limitations over these souls and making their lives dependent on the decisions made by their hosts.

-A system can only achieve freedom from the binding when their hosts successfully becomes an Ultra Tasker and ascends to The Realm of Realms. I.e, By successfully assisting a Tasker till they reached the top, they had atoned for their crimes.

T:

TASKERS:

Inhabitants of realms who have been seen as unfortunate by the Soul realm's standards so at the time of their deaths, they are offered a chance to either choose reincarnation or become fixers of the balance of the Task realms (aka, Taskers)

TASK REALMS:

Products of Genesis. These realms enable the utmost functioning of the Realm of Realms and The Anti-Realm of Realms. When these realms are in a balanced state, they release pure energy to the Realm of Realms (this strengthens the RoR).

-When the Task realms are not in a balanced state, they release chaos energy into The Anti-Realm of Realms (this strengthens the ARoR)

-This is why both sides are always fighting for dominance over the balance of the Task realms.

TEST TASK:

-This is a task done by a Tasker before every level upgrade. It is mandatory that a System does not follow their hosts into the task realm during a test task. (This is the only time when the distance limitation rule is null and void.)

-After every test task, a Tasker's general stats are adjusted appropriately.

THE REALM OF REALMS:

-This Major realm came out of The Source right after Genesis. It is the balance of Genesis and is responsible for keeping the balance of the Task realms and is also considered the Utopia for Taskers. The first entities to appear in The Realm of Realms are the First generation systems.

THE GUARDIANS:

-Widely know as The Upper echelons. One thing to note is that their existence serve as a check and balance to the First generation systems hence all First Generation systems are bound to a Guardian. (I can't say more for now.)

THE ANTI-REALM OF REALMS:

-This is the last major realm to emerge from the Source. It is the imbalance of Genesis and is responsible for the break down/destruction of the Task realms. It is the home of all Reapers. 

-For every Task realm that is destroyed, a Soul is born from the residual essence. These souls then serve as Systems and are assigned/bound to the Reapers to work hand in hand and destroy more Task realms.

-Unlike the Systems of the Taskers, the Systems of the Reapers do not have strong limitations (but they do have limitations e g, they can't kill an inhabitant of a realm) and their lives or death isn't dependent on their hosts. Rather, both Reaper and System work hand in hand to survive in the Anti-Realm of Realms.

-It is also possible for the Systems of the Reapers to change hosts frequently as the death of their hosts has to effect on them except weakening them for a while.

THE SOURCE: 

-Chaos. Organized Chaos. Unorganized Chaos.

-A swirling mass of darkness that is the birth place of everything. The exact location of The Source is unknown. It is everywhere and nowhere at the same time. It exists in the strands of each realm and it also exists in the life essense of every soul.

-The Source is everything and nothing at all.

-Every single thing in existence was indirectly birthed from The Source. The only three things that came directly from The Source were; The Realm of Realms, Genesis and The Anti-Realm of Realms.

Tell me in the comment section if there's anything you all don't understand or if there's an explanation that I missed.