Faolyn
(she/her)
In D&D, it might be worth considering where the gods come from. If the gods were here first, then perhaps there was a grab bag of portfolios of every possible facet of existence, and so some gods just drew the "evil" aspects. Perhaps that's what turned them evil in the first place. It's hard being made the god of murder while remaining a good being. OTOH, if mortals made the gods out of their belief, then sure, fear and hatred and other evils would create evil gods.
Of course, people aren't going to be the only ones making gods, in such a setting. I'm reminded of The Flesh from The Magnus Archives--an entity that represents the fear of physical mutilation and being butchered as nothing more than meat, born out of the fears of livestock and other animals bred as food. And because it was an animal-created Fear Entity, it interacts with humanity weirdly.
And there's a third option (the Discword option), where you have godlings that latch on to any belief or strong emotion and gain power from them. Imagine a murder of passion. Some godling is nearby and is empowered by the fear and anger behind the murder, and that causes it to seek out similar events. Eventually, it becomes a grown-up god of murder.
As for archfiends (and archfey, and... archangels), personally, I don't see a problem in also having them, even if they have portfolios similar to those of various gods. They're trying to become gods, after all, and while there may be (by the cosmology's RAW) a wide gulf between such creatures and actual gods, worshipers aren't going to be able to see that gulf, assuming they even know it exists.
Of course, people aren't going to be the only ones making gods, in such a setting. I'm reminded of The Flesh from The Magnus Archives--an entity that represents the fear of physical mutilation and being butchered as nothing more than meat, born out of the fears of livestock and other animals bred as food. And because it was an animal-created Fear Entity, it interacts with humanity weirdly.
And there's a third option (the Discword option), where you have godlings that latch on to any belief or strong emotion and gain power from them. Imagine a murder of passion. Some godling is nearby and is empowered by the fear and anger behind the murder, and that causes it to seek out similar events. Eventually, it becomes a grown-up god of murder.
As for archfiends (and archfey, and... archangels), personally, I don't see a problem in also having them, even if they have portfolios similar to those of various gods. They're trying to become gods, after all, and while there may be (by the cosmology's RAW) a wide gulf between such creatures and actual gods, worshipers aren't going to be able to see that gulf, assuming they even know it exists.