They are evil. You can turn on your detector and know, with certainty, they are evil.
To be fair Mistwell, there is no ‘evil’ detector in 5e. The Ol’ Paladin Paradigm of:
“
If it glows, kill it” of prior editions, and the Detect Evil spell is gone.
Some Cleric spells have riders, that state, the appearance of a spell, like
Spirit Guardians, is determined by the
Alignment of the Cleric, (not their god). If played this way, these spells will unequivocally reveal the Caster’s Alignment.
That said, such verbiage in spells like Spirit Guardians, has
zero mechanical game balance, and thus,
for me, are flavor text...to be used or ignored at will.
The Raiders of the Lost Arc, Arc of the Covenant, would be EVIL, by RAW, since the effect it produces...an extra large Sprit Guardian effect, is clearly more Fiendish than Angelic.
Skulls that melt your face off if you look at them, is not your typical imagery for smiting Angels in Christian Iconography, for example.
But those settings and tables aren't the default.
As I stated , in a prior thread...Default has two usages.
In contractual terms, it means a failure to fulfill a bond, requirement, or obligation.
In the 5e Monster Manual, (I believe it is page 7), states very clearly, that the Alignment listed can be changed,
Freely, and
with no restriction.
So ‘Default’ in a D&D context for Alignment,
can not mean a breach of obligation to the rules, or intent of the rules.
Thus the ‘Default’ of D&D Alignment must be evaluated, in the second common usage, which is akin to computer games and electronics:
an arbitrary position, that can modified, or not modified, at the aesthetic and arbitrary whim of the end user.
A D&D Argument, made on the foundation of ‘Default Settings’ has the same weight as saying an electronic game must be played with a certain Gamma Resolution....which to me, is almost zero weight at all.
Modern Games allow for Setting alterations to be made, to fit, one’s individual taste. Period.
To Parody a Black Flag song, if you want to do the following:
“
D&D Party Tonight!
We're gonna have a D&D party tonight
All right!
We're gonna have a D&D party, all right
Tonight!
We've got nothing better to do
Than kill some Orcs and have a couple of brews”
No problem, it is fun, and you do not
have to contend with granular moral distinctions.
It is not,
however the presumption, inherent in the mechanics of the system, as it was, in the historical past of D&D.
The game has moved
beyond that paradigmatic presumption, while,
simultaneously being backward compatible with the old paradigm.