How about
Spell-like Abilities (Sp): Caster level X.
At-will: detect chaos, detect evil, detect good, detect law
?
Well, if we want to reflect the original description, it'd be something like:
Alignment Sight (Sp): As a full-round action, a busen can view the alignment aura power (chaos, evil, good, or law) of every creature, object or spell it can see within a 60 ft. cone. To determine a target's aura power, see the
detect chaos,
detect evil,
detect good, and
detect law spells. The busen is never stunned if it detects an overwhelming aura with an alignment opposite to its own. This power requires line-of-sight and is blocked by fog, darkness, and other factors that limit normal sight. It cannot see through cloth, so is useless against creatures wearing garments that conceal their entire body and face, such as hooded cloaks. Busen usually demand intruders disrobe and remove all weapons and jewelery before using Alignment Sight, to prevent the intruders concealing aligned objects and creatures in their clothes.
This is the equivalent of a
Xth level spell (caster level
Y).
Or this.
Detect Alignment (Sp): A busen can examine the alignment auras of every creature, object and spell within a 60 ft. cone. This give the busen the same information as studying the area with the
detect chaos,
detect evil,
detect good, and
detect law spells, except it registers all alignments simultaneously and the busen is never stunned if it detects an overwhelming aura of an alignment opposite to its own.
Thus, in the first round it detects the presence or absence of chaos, evil, good, and law. On the second round it determines the number of chaotic, evil, good and lawful auras and the power and alignment of the most potent aura present. On the third round it determines the power and location of every chaotic, evil, good and lawful aura within the area of effect.
This is the equivalent of a
Xth level spell (caster level
Y).