By means of a delude spell, the wizard conceals his own alignment with that of any creature within a 30-foot radius at the time the spell is cast. The creature must be of higher than animal intelligence for the spell to work; its own alignment remains unchanged.
The creature receives a saving throw vs. spell and, if successful, the delude spell fails. If the spell is successful, any know alignment spell used against the caster discovers only the assumed alignment.
Note that a detect good or detect evil also detects the assumed aura, if the aura is strong enough. The creature whose aura has been assumed radiates magic, but the wizard radiates magic only to the creature whose alignment has been assumed.
If a delude spell is used in conjunction with a change self or alter self spell, the class of the wizard can be totally hidden, if he is clever enough to carry off the disguise.