Alter Aeon Online Help

Keywords are:  'mage spell detect see invisibility mass invisible'

Spell: detect invisibility      Mana:  12  Int: 21  Wis: 17  Lvl 15 Mage  (28%)
                                (important)   Requires: dancing lights
                                Group: Mage illusion spellgroup
                                (Can Be Maintained)
Spell: invisibility             Mana:  45  Int: 28  Wis: 24  Lvl 24 Mage  (28%)
                                (obscure)   Requires: displacement
                                Group: Mage illusion spellgroup
Spell: mass invisibility        Mana: 105  Int: 35  Wis: 31  Lvl 34 Mage  (21%)
                                (obscure)   Requires: invisibility
                                Group: Mage illusion spellgroup

Usage:
cast detect invisibility
cast invisibility <target>
cast mass invisibility

The most important of these, and the only one commonly taught, is 'detect
invisibility'.  This detection spell can only be cast on yourself, and
allows you to detect other invisible items or people.

The actual 'invisibility' spell is rarely taught, and is rarely useful.
Because the spell to detect invisibility is so low level and easy to
cast, even the most low level peasants use it. Magical creatures such
as fairies, demons, angels and dragons can see through invisibility
spells. It is most useful for avoiding animals, however many aggressive
predators rely on scent and can still sniff you out.

Additionally, other spells you may have cast on you can reveal your
presence.  'Faerie fire' and 'fairy fog' reveal a faint outline, and while
you remain invisible, the bright white aura of the cleric spell 'sanctuary'
can still be seen.

Invisibility is castable on others.  Invisibility will not fade when
attacking, and can be an advantage when fighting creatures without the
ability to see you.

'Mass invisibility' is a powerful mage spell, used to cast invisibility
on an entire group of characters at once.