The Disc is a wonderous and magical place. Well, it's magical at least. Many have asked why this is the case, when so many other worlds of the multiverse are content to avoid raising their heads above the parapet of reality. To this question, the priests and philosophers of the Disc simply reply: "The gods love a joke as much as anyone else."
Other guilds can make use of magic, but only to a limited extent, and only with assistance (direct or otherwise) from a wizard or witch. For example, they can cast a spell from a scroll scribed by a wizard, or wear a magick crystal imbued by a witch.
Wizard magic tends towards the spectacular; the conventional wizard likes their spells to advertise the caster's puissance. Witch magic, conversely, is a lot more subtle - often masking its magical use with seemingly mundane actions.
Central to magic use is the casting of spells. A magic-user must first learn the spell in question, committing it to memory. They may then attempt to cast it. Alternately, anyone may cast a wizard spell from an appropriate scroll.
In order to cast a spell, several checks must be passed:
- The caster must have enough magic GP remaining.
- The caster must have the correct components.
- The caster must pass skillchecks against the various stages of a spell.
More detail on each of these is as follows:
Guild points and magic
Each spell has a guild point cost associated with it. This cost is taken from their magic guild points. The maximum magic guild points a player has is equal to their magic.points bonus plus 50, and a player may view their remaining magic guild points using the 'gp' command.
If a player does not have enough magic guild points remaining to cast a spell, then they are simply prevented from attempting to do so. Otherwise, the guild point cost is subtracted as they start to cast the spell; they lose the GP whether they subsequently succeed or fail in casting.
- The amount of thaums is a fifth (1/5) the headspace of the spell. Thus if the spell has a headspace of 10, 2 thaums are released into the room.
- The thaums are added when casting a spell begins, when the caster is shown "You prepare to cast Spell Name [on <Thing|Living>]."
- One can calculate the headspace by calculating how many thaums are added to the room when casting a spell. However, since thaums in a room decay, it is best to do the testing in a room without any thaums. Also, to prevent the thaums decaying before you read it, it is also best to paste the commands to stop and to read a thaumometer as close as possible to the "You prepare" line. Repeating the experiment in a new room also helps prevent erroneous results.
Some spells require components in order to be cast - items which are necessary in some way for the completion of the spell. These components may range from corpse parts, to herbs and vegetables, to specialised arcane items.
Components may simply be required to cast the spell, or they may also be consumed during it. As a rough guideline, offensive spells almost always require components and consume them, whereas other spells tend to be less demanding.
It is necessary to possess all the required components before spellcasting can start; however, they are not necessarily used or consumed at this point. Each spell has a number of 'stages' associated with its casting, and the components are either used/consumed at one of these stages, or upon the spell's completion.
Note that it is possible to lose components between starting casting and reaching the stage that requires them (for example, due to fumbling them) - in this case, the spell will fail at that stage.
Unlike most mundane commands on the Disc, there are frequently several skillchecks that must be passed against a variety of skills in order to successfully cast a spell.
Each stage of a spell has its own individual skillcheck associated with it. Usually, this is against a skill under the magic.methods.* skilltree, though there are some exceptions (for example, Gillimer's Ring of Temperate Weather checks against crafts.smithing.gold).
Many of these skillchecks are performed on a pass/fail basis - if the check passes, the spell succeeds, otherwise it does not. Other skillchecks are more qualitative, determining something about the spell's results. For example, the caster requires a minimum level of magic.methods.physical.enchanting in order to cast Brother Happalon's Elementary Enchanting, but this skill also determines the degree of enchantment imparted by the spell on completion.
Spellcasting can be interrupted by various means:
- If the target leaves the room, or otherwise ceases to be valid (eg. due to death) then the spell is interrupted (though not necessarily immediately).
- If a spellcaster is damaged during spellcasting, there is a skill-dependent chance based on the amount of damage they took that their concentration is disrupted by the pain, ending their spellcasting.
- The caster may choose to abandon their spell via 'stop' or 'stop spell'.
Some spells may inflict damage on the caster of an interrupted spell, depending on how far through the casting process they had got. For example, Pragi's Fiery Gaze will burn the caster if abandoned late in the spell.
In the event that the caster fails their spellcasting, any of the following may occur:
- Nothing at all.
- The caster suffers a minor (non-damaging) inconvenience, such as:
- Garlic breath
- Falling asleep
- A backfire occurs - some degree of the spell's effects are applied to the caster instead of the victim. This can cause quite serious damage (especially with more powerful casters and harder spells), and is often a leading cause of death for wizards. Witch spells, on the other hand, do not usually inflict backfires - only Mama Kolydina's Instant Infestation and Mother Feelbright's Busy Bees are known to be able to cause damage to the caster.
See also standard spell failures.
There are a number of magic items to be found, bought or constructed on the Disc. Many of these are unrestricted in their use - magic-users and non-magic-users alike can make use of them. All magic items, however, require their user to pass a skillcheck in order to gain any magical use out of them. For example, a blue crystal ring may be worn by anyone, but requires a skillcheck against magic.items.worn.ring in order to be used to teleport.
Many magical items have a number of 'charges' associated with them - or in other words, a number of times that they can be used. These items can be recharged by a wizard, though the process often involves some risk for the wizard concerned.
Most magic-based attacks differ substantially from conventional attacks, in the following ways:
- They usually automatically hit the target, assuming that target is still in the room once the spell successfully completes. Hence, no amount of dodge, parry or block will help against most magical attacks.
- Likewise, they usually ignore armour and similar defences (such as Chrenedict's Corporeal Covering).
- Magical attacks may be area effect attacks, striking everyone within the same room simultaneously.
- Some targets are completely immune to certain magical attacks. For example, a target without ears cannot be affected by Effermhor's Hypersonic Assault, likewise a target without nose and lungs cannot be affected by G'flott's Olfactory Nightmare.
- Many magical attacks have other effects instead of (or in addition to) actual damage. For example, hedgehog lowers the target's skills.
- Some magical attacks can be resisted or have their effect diminished depending on the victim's bonus in a particular skill. For example, tempt can be countered by a good bonus in magic.methods.spiritual.abjuring.
Magic and the environment
Some areas of the disc are high in room enchantment - thaumic energy which can affect (and sometimes pose a hazard to) spells cast in its vicinity. Similarly, the casting of spells (and use of some magic items) can, intentionally or otherwise, increase or decrease the dynamic enchantment part of a room's enchantment. The other part, the background enchantment, doesn't change.