What, Exactly, Are Ferals?

For years, mages have employed familiars for various means. It is in the nature of a mage to seclude himself from society, so having a familiar to perform small tasks for them that cannot be entrusted to a maid or butler is almost essential to maintaining an acceptable standard of living. 

There are various means for creating a familiar. The most common is to place the lingering thoughts of a dead person in a dead animal. Then a piece of the magus with a high number of magic circuits such as hair or blood, is placed in the animal, and it is repaired.

A familiar made in this way will have it’s own thoughts and personality, independent of the mage. It can use magecraft, but cannot generate its own prana, and is thus dependent on their master. The magus shares a mental connection with their familiar, even though the entity is separate in almost all other ways.

A servant is often thought of as a form of familiar, as they also share a mental connection with their magus, and are depended on prana from the magus to replenish their own. However, servants are in a class far beyond that of a typical familiar. A servant is a copy, a reflection of a heroic spirit, summoned into the world through the power of the holy grail, and bound to a magus through a special contract. The magus acts as the focal point that allows the servant to exist in this world.

However, since the destruction of Fuyuki in the last Holy Grail War, this seemingly immutable law has been rewritten. Fragments of the grail scattered across the continents have allowed servants to exist free of any contract or master. Dubbed ‘Feral’ Servants, these entities wander the realm, reenacting, and expanding their legends and power without restraint. Though they are still unable to create their own prana, the precious energy can instead be drained from the soul of a living human, often killing them in the process.