On many levels, that's a complex question...

On Earth, we really don't see true evil. Or at least, the "true evil" we see is actually depraved indifference, extreme narcissistic callousness in the pursuit of personal goals to the point that everyone else sees that individual as "evil"

In other words, very few people think they are evil, or are "evil for evil's sake"

If you consider some of the worst Earth offenders: Hitler, Mussolini, Stalin, Pol Pot (and the Khmer Rouge), Saddam Hussein, the little Kim's of Korea, Ossama Bin Laden...

All of them had definite goals and were relentless in the pursuit of those goals to the exclusion of (almost) everyone and (almost) everything else. They caused immeasurable amounts of death and destruction, but it was always in the pursuit of some higher goal they didn't consider "evil."

But in fact, to all objective standards, they were evil in their misguided ways.

I think one reason we don't see "Evil for the Sake of Evil" is that Evil is generally defined in opposition to "Good"

Just as Earth doesn't have many truly evil people, we also don't have that many truly Good people. Or at least people who go around calling themselves good. (Which would be hubris--a sin) Most "Good" people have faults and fail at being good.

Now, that being said.

Astlan is similar, but much more polarized. There definitely are people (and specifically Gods) that define themselves as "Good" in the Multiverse that Astlan deals with. Thus it is extremely likely that their enemies may choose to declare themselves "Evil" and, if they happen to be truly depraved in their indifference to others and their narcissistic callousness they may revel in their own "Evil" actions and nature.

And this is actually something I want to explore in the later books and most of my other books. What is Evil?

In Astlan, life, for the most part is cheap because for non-atheists there is an afterlife. Demons are immortal with a few exceptional events/things able to take them out.

Thus things or people that permanently "Kill" or destroy other souls/spirits/animus are one of the closest things I can think of to "Evil"

Thus soul sucking swords, certain undead, necromancers and other "monsters" are evil because they drain others of their animus and can eventually consume/destroy or obliterate those individuals. Thus they are truly evil.

Unless, of course, the only way those creatures/devices can survive is to consume others. Then they are just trying to continue their own existence.
That's not necessarily apriori evil. For example, if you assume an Atheist position on earth, that there is no afterlife. Eating animals to survive would be evil, because you are permanently killing them. OK, for humans it's a choice, but what about wolves or other carnivores? Are they evil?

So in my mind, and in these books it's going to be complicated.

However, more short answer, but building on above.

Yes there are beings (dark gods, some demons and others) who "consider themselves to be evil" and go out of their way to inflict pain and suffering and true death on others.

However, there are also some individuals who aren't trying to "be evil" but who may end up being more "evil" than some that were trying to be evil.