Though I do agree that it is almost impossible to define good and evil
I think to say one does all things because it is in ones nature is a bit of a cop out.
If it is in my nature to kill for food then it is indeed is not an evil act but there are those
that kill for pleasure, we label them insane because they have lost their "moral compass"
but isn't that the base pre-requisite for the general label of evil? to lose all socially acceptable
thought allows for an entirely selfish, cruel and diabolical nature. anything less is mere
expediance. sentient insanity is perhaps the very beginning of evil...
Playing by ones own rules is not the same as playing to ones nature. ones nature is judged
by the universal standard for sentient thought: natural gravity is required with need trumping
desire, desire trumping logic. ones nature is heavily understood by this method of measure.
discipline can moderate and adjust the order but never shatter it.
to be evil there is a shattering of the natural cause widely assumed to be unintentional. a self awareness
must be present though and that self awareness must advocate nothing but ill-intent and desire regardless
of logic and regardless of need.
To find such a character in the malazan books of the fallen is highly unlikely even if several
characters fall pretty close to the description.
I would develop my list of likely evil in this way:
1) Kallor
2) Raest
3) Pannion Domin
Kallor posseses a history that floats on the philosophy of might makes right. this is not an evil
philosophy, in a way it even follows the logic of the natural world. Where Kallor lost a tenable
moral foothold is in his irrational incursion of his law indescriminately on all creation. any system
must have exception to survive let alone exist. This is because we all know no logic is perfect
thus no rule is perfect.
Kallors actions of pure malicious selfish greed go even beyond that. his burning of his kingdom was unnecesary,
there was no rule behind it. he thus held to a shattered logic and it warped the very purpose of desire. he is the closest I see to the model of "evil" I understand.
Raest follows suit in his tyranny and so did the pannion. In my opinion a tyrant absolutely corrupted by power
is the closest humanity will ever come to pure evil...just my opinion though