This is a detailed guide into the structure and rules surrounding the Holy Grail system adopted by the "Arena admins". It takes most of its basis from the official Holy Grail War system in the Nasuverse. However, it has some differences to better accommodate it into the Arena mythos, which will be explained in this guide.
The Holy Grail War is a war fought between magi, contesting for the Holy Grail which will grant them their wishes upon acquisition. The war is usually fought between seven teams of masters and their servants, though sometimes variations of the system can occur, giving room for more participants. A winner is declared only when all other masters have surrendered or been slain, and all other servants have been defeated.
The Arena variation of the war isn't too different. The same kind of system occurs, where the winner is granted access to the Grail and gets to make a wish. Since the Grail is in the hands of the Arena admins, it is free from any corruptions it may have had in its original setting. Thus, alterations of the system like 8th teams or corrupted Grails are non-existent. However, new types of alterations may occur due to "tampering" with the Grail itself.
There are 7 Classes of servants that can be summoned in the war: Saber, Archer, Lancer, Rider, Caster, Assassin and Berserker.
Masters & Heroic SpiritsEdit
In a usual Holy Grail War, seven masters gather to participate. These seven individuals are usually magi. In the Arena setting, masters can be anyone (of course, being a magus increases your efficiency in the war). Non-magus masters are given a supply of prana that they can use to accommodate their servant; magus masters will have an amount of prana according to how much they usually wield. Prana will be explained more later on.
As for Heroic Spirits, they are largely unchanged. Heroic Spirits are summoned from the Throne of Heroes, and they can be from the history of Earth, or from fiction that has gained fame (like a fairytale). Certain abberations can occur depending on the master and the ritual performed to summon the Heroic Spirit.
Heroic Spirits are summoned as servants to masters through the summoning ritual. Usually, when a ritual takes place, the Grail assigns a Heroic Spirit to the master based on good compatibility. This clause can be bypassed by using catalysts, which are artifacts linking to historic figures. Doing so, however, does not guarantee compatibility between master and servant. If not enough masters have performed the ritual in time for the war's initiation, the Grail will forcefully choose random individuals among the local population of the Grail's current location until all vacancies are filled. This does not happen in Arena, for the masters are each summoned to the fray anyway.
When summoned as Servants, the Heroic Spirits will be assigned parameters and abilities based on what they had/achieved in life, the Class they've come in under, and various other factors.
Prana is the Nasuverse equivalent of mana. It is the magical resource magi and Heroic Spirits use. In fact, it is more like the life-force of Heroic Spirits. When summoned as servants, they require a supply of prana to remain in the world. This supply is usually granted by the masters. If a master runs out of prana, they will be rendered incapable of controlling a servant. In most cases, masters die when they run out of prana.
Prana can be gathered in a multitude of different ways. It exists in every living thing, so "harvesting" can take place through the mass absorption of many living things. Some objects may also contain prana, such as magical items or holy relics. Prana is also present in the very air of the world, but in such minute quantities that it is barely noticable. In some places, however, there are "prana vents" where the concentration of prana is greater than normal. In some cases, these vents are enough to even sustain servants without masters.
Only the Archer class is capable of sustaining themselves off their own prana when away from masters. Other classes will become weakened and eventually disappear if they stray too far and long. Servants also use prana for their abilities and Noble Phantasms. If a master cannot supply a sufficient amount of prana for the servant's powers, they will unable to use said powers.