=====CLASSES=====

The VRMMORPG "Horus" has six basic classes. Characters pick their class upon reaching Level 5.

Warrior: Specializes in the use of melee weapons. Broad equipment choices allow for high versatility and survivability. Main stats: Agility & Strength.

Boxer: Fights using martial arts and other unarmed Skills. Huge crowd control potential, as well as the ability to bypass many common defenses against swords and guns. Main stats: Strength.

Sniper: Only uses ranged weapons. Can unleash devastating attacks when given enough preparation time, but this can be difficult without the support of allies. Main stats: Dexterity 

Esper: Draws upon psychic powers to control the elements and manipulate the laws of physics. A very difficult class, but with enormous late-game potential. Main stats: Intelligence & Energy.

Engineer: Uses mechanical knowledge to craft robotic pets, armor, and other gadgets. Can create a huge advantage before a fight begins, but can't easily recover if inventions are destroyed during a long fight. Main stats: Intelligence & Energy.

Hunter: Summons powerful war beasts and wields a variety of ranged weapons. Learns a variety of supplemental Skills to help it survive in the wilderness. Main stats: Dexterity.

After giving the list some careful thought, Apophis realized that it would be best to choose his old life's class, after all. He was deeply familiar with it… and also had a few powerful Skill Books to support it. 

Each class is strongest when the player focuses on two of the game's main stats.

=====STATS=====

STRENGTH (STR): Physical attack and endurance, as well as increasing lifting capacity and other athletic feats. Most useful for Warriors and Boxers, but also beneficial for any character who wants to boost their defenses.

AGILITY (AGI): Attack rate, movement speed, and reaction time. Vital for Snipers and extremely useful for Warriors, but never a bad investment for any character.

DEXTERITY (DEX): Concentration, focus, and precision. Careful aiming at long distances or assembling a complex robot in the middle of a tense battle benefit from this stat. Most important for Snipers, but also very useful for Engineers and Hunters.

INTELLIGENCE (INT): Increases the power of some spiritual and psychic Skills. Speeds the acquisition of new languages and areas of academic expertise. Unlocks some branches of the Talent Tree, especially for more complex classes. Most important for Espers and Engineers, as well as characters who wish to study the ruins of ancient civilizations.

ENERGY: A pool of cosmic power which player characters must spend to use their Skills, similar to mana in other games. Attacks which have been empowered by Energy can affect certain targets which are immune to ordinary attacks.

=====TALENT TREE SKILLS=====

Each class has access to a Talent Tree, which allows characters of that class to gain Talent Tree Skills. These usually provide a character's core abilities, and usually scale in effectiveness based on the class's two main stats.

Classes which are more difficult and complicated usually have more complex Talent Trees, though their Skills tend to scale differently. For example, Mechanic has a very complicated Talent Tree which can be confusing for new players. On the other hand, Warrior has a much simpler Talent Tree.

A low-level Mechanic without much game knowledge may find itself almost as useless as having no class at all. They might, for example, choose several Talent Tree Skills which allow them to make agile combat robots with powerful area of effect abilities but which are almost useless against armored targets, and so be unable to kill valuable enemies.

Meanwhile, a similarly unknowledgeable Warrior might be very powerful at this same stage, simply because they can allocate Skill Points to basic attack and defense Skills and easily fight powerful enemies.

However, at LVL 20, a knowledgeable Mechanic might be able to manage an entire miniboss encounter on their own because they were able to prepare a whole army of combat robots and gadgets, while the knowledgeable Warrior of the same level would be overwhelmed by the same encounter, unless they also had powerful Book Skills.

=====SKILL BOOKS=====

Skill Books are the primary way characters create unique builds. Skill Books are valuable items which allow characters to learn new active and passive Skills to supplement their Talent Tree Skills.

Most Skill Books are locked to one (or sometimes two) classes, but some are universal and can be used by any character.

Skill Books often supplement one of a class's main play styles. For example, one branch of the Sniper Talent Tree focuses on abilities which force the Sniper to remain on one knee or in a prone position while their Skills charge up, but then grant those Skills additional power and effects.

Many Sniper Skill Books indirectly enhance this branch of the Sniper Talent Tree. For example, allowing a Sniper to pause a charging Skill instead of canceling the charge while changing position, or creating an energy shield directly in front of their gun's barrel, which will protect them from the front while lying prone.

All Skill Books are unique, and are consumed upon use.

=====SKILL POINTS=====

Characters gain 1 Skill Point with every new level, and sometimes receive a few Skill Points as quest and achievement rewards. Talent Tree Skills and Book Skills can both be upgraded in damage and utility by spending Skill Points on them. However, the method is different for each.

Talent Tree Skills receive a slight power boost with every point added to them. For example, a Hunter's ~Land Shark~ combat pet will gain a tiny boost to its combat stats with every Skill Point spent on the Skill used to summon it.

However, Book Skills instead have a large Skill Point cost associated with evolving them to the next tier. For example, a Hunter's ~Void Kitten~ combat pet is not very powerful, but if the Hunter spends 30 Skill Points, it can upgrade its summoning Skill to the far mightier ~Void Cat~ combat pet. Another 50 Skill Points will evolve it into the ferocious ~Void Tiger~.

Active Skills of both kinds require Energy to cast. As the Skills are upgraded, the Energy required to cast them rises. It is possible for a careless player to upgrade a Skill so much that they no longer have enough Energy to cast it.

Because of this, it is often better to upgrade a variety of Skills, rather than spend every Skill Point on one Skill.

=====CHARACTER POWER=====

A character's level is very important at the beginning of "Horus." Reaching Level 5 allows a character to choose a class and to start earning Skill Points, after all.

In addition, reaching Level 5 allows a character to evolve their race, changing from a basic human to another form with higher base stats and other characteristics. In fact, the first stage of evolution is what awakens the ability to use cosmic Energy in the first place.

Finally, characters even without classes receive boosts to their stats with every level they gain until Level 10, when they choose their second evolution, the choice of which is influenced by their actions in the game and the cosmic forces they've come into contact with.

From this point on, characters gain no more bonuses to their stats simply from leveling, though they continue to gain Skill Points by leveling.

From this point on, the main way a character grows in power is by completing difficult quests and Dungeons to receive powerful items, Skill Books, and rewards of bonus stats and Skill Points.

Because character level is a poor indicator of true power, "Horus" also provides a letter rating which calculates a character's rough power level in comparison to other entities in the game.

Almost all characters in the game range from F Rank to S Rank, with A-Rank characters being at the level of cosmic gods. There is some nuance within these tiers, and a character could be described as at, for example, B- or C+.

A character at C- Rank might be able to defeat a character at C Rank, but the threshold between letters is so vast that a C+ character is very unlikely to defeat a D- character.

=====ITEM QUALITY=====

COMMON: Most items are Common and provide very basic capabilities. As the game difficulty increases, Common items, even of high levels, become less effective at dealing with those threats.

RARE: Much more powerful than Common items. Usually provide additional special effects compared to items of a similar level.

EPIC: Extremely powerful items which can provide huge boosts to a certain play style. Often restricted by class. Usually found in difficult Dungeons or as rewards for unique quests.

LEGENDARY: Items so powerful that they played a role in the shaping of galactic history. Usually belonged to heroes or gods from bygone ages. Often have mysterious effects which are not immediately apparent.

ARTIFACT: Unique and impossibly rare items. Almost nothing is known about them, except that they can be obtained from IronMan-difficulty Dungeons.

=====DUNGEONS (Spoilers for Chapter 16)=====

Dungeons are instanced zones filled with extremely difficult monsters. Each Dungeon can be attempted at one of five difficulty levels, each of which usually represents a different time in the dungeon's history, requiring a player to complete each difficulty level to uncover the Dungeon's full storyline.

Throughout the first ten years of the MMORPG Horus's existence, dungeon completion rates of the following difficulties were recorded:

EASY: 80-85% success rate.

NORMAL: 30-40% success rate.

HARD: 1-10% success rate.

NIGHTMARE: 0.1%-10% success rate.*

IRONMAN: 0% success rate.**

=====

* Nightmare Dungeons offer much higher difficulty for most players compared to Hard, but do not meaningfully challenge elite players more than casual players, as they simply rely more on tactics and knowledge which elite players have already mastered. For this reason, Nightmare Dungeons have a much lower success rate among casual players compared to Hard Dungeons, but nearly the identical rate of completion for elite players.

** Only one party has successfully completed this difficulty level. Due to the incredibly low success rate, "Horus" displays this very small decimal as "0%."