usage: cast <spell name or #> on <player/monster/item> <x>
 
This allows you to "naturally" cast spells that you have learned. Some spells
are offensive (blast, langour, etc) and may be cast on other players or
monsters. Some spells work only on items (enchant for example). Some spells
only work on yourself or other players (healing for example), and finally 
some spells affect an entire area (such as sleep or summoning). Casting a 
spell uses magic points, the number of which depends upon the individual 
spell. In the case of offensive spells, the target has a chance to dodge the 
spell.

You learn spells by finding scrolls. To learn a spell you must find a monster
that has the appropriate scroll and either kill it solo (i.e. no one else can 
have attacked the monster - you must kill it all on your own), steal the 
scroll or cause the monster to flee from you. Once you've learned a spell, 
your psychic ability stat determines whether or not you can actually cast it. 
The minimum psy requirement to cast a spell is equal to the level of the 
monster that carries the scroll for the spell. I.E. if a level 20 monster 
carries the lightning scroll, you must have a psy of at least 20 to cast the 
spell (without the aid of a psychic focus).

The mage classes (cleric, mystic, sorcerer) can use "psychic focus" devices
to both allow them to cast spells that they couldn't otherwise cast because
of insufficient psy, and also to boost the power of the spell.

Non-mages can also use psychic focus items to (possibly) allow them to cast 
spells that they couldn't otherwise cast because of low psy. A psychic focus
will affectively double your psy (for the purposes of determining whether or
not you can cast the spell in question). If your doubled psy is now high
enough, you cast the spell.

Spells may also be cast (via the 'use' command) with the aid of magical 
devices (wands, rods, orbs, etc.)

See the magic help section for information on the individual spells.

