Does Detect Evil allow you to detect characters with an evil
alignment? Many players would answer that the question is obviously yes,
and the answer is 'Yes', but it is not so obvious.
In 3.5, there appear to be 3 designations of evil. There is
an "Evil alignment", and "Evil aura", and an "Evil
subtype".
The Detect Evil spell clearly tells us that the caster can
detect creatures with an "Evil aura", but the PHB also tells us that
most characters do not have a good or evil aura. Only clerics and paladins have such an "aura". (PHB
32). There is no "Detect Alignment" or "Know Alignment"
spell in the PHB, so I don't think a character can be revealed to be Chaotic
Neutral, but characters can be identified as Good/Evil/Lawful, or Chaotic.
I have deduced that "Detect Evil" does reveal any
evilly aligned character by looking at the chart on page 219 of the PHB showing
"Aura Power". In it, there is a line for "Cleric of an evil
deity". Per that line, a 1st level evil cleric would have an aura
power of "faint", and a 3rd level evil cleric would have an aura power of
"Moderate", and a 5th level evil cleric would have an aura power of
"Strong".
Given this clear interpretation, then what is the value of the first
line in the chart for "Evil creature"? I deduce that the first
line can only apply to creatures that are of evil alignment but that do
not have the Evil subtype (line 3) and are not Evil Clerics or Paladins (line
4).
So, a 9th level evil rogue will have a "Faint"
"aura power" of evil, the same as a 1st level evil rogue. A
12th level evil rogue will have a "Moderate" "aura power" of
evil. Even though rogues do not have auras, they still have "aura
powers" for purposes of the detect evil spell.
