Sakurai the Cursed
My point is that he is literally the only Darkness Spirit we have seen that didn’t want to consume the world. We haven’t seen even one other “good” darkness being, whereas we have seen both good and evil from every other element.
It'd be helpful if you could better define what you're talking about, because I'm a little unclear. You say that he's the only Darkness Spirit we've interacted with that hasn't been evil, and I do think that's true, but that's because the only Darkness Spirits we've interacted with other than him have been evil members of the ShadowScythe. And that's because our interactions with Spirits in general are very rare. I'm not counting standard Elementals here because while from what we know they're also Spirits from the Elemental Realms (using the crystals on their bodies as their "items" to possess according to Ash), they almost all seem to be rather mindless and savage. All in all, I can only think of 3 Elemental Spirits other than the Avatars and the ShadowScythe that we've actually talked to (and Nythera talked to 4, but they all attacked her for not bowing to their infinite superiority, so... not sure if we wanna count them), those being the ones we go to in order to acquire the Primalization of the elements of the Prime Orbs we didn't touch. 4 if that's what the Old Man of the Mountain is. So if you do mean Spirits specifically, then can you give examples of this "both good and evil from every other element"? If not, is it really fair to do any sort of comparison? Because from what I see, we see a lot of evil Darkness Spirits simply because the stereotypical Evil Faction™ in DF just happens to be a group of evil Darkness Spirits.
If you mean beings related to Darkness in general rather than Spirits from the Elemental Realms specifically, well, we've seen plenty of good Darkness beings and I hardly think that the petty evil of the non-ShadowScythe Darkness bad guys is as lofty as "wanting to consume the world". It is true that Darkness monsters in general are a majority, but that's partly because of the ShadowScythe controlling/commanding them (it's kind of unclear how sentient they are, really) and admittedly also partly due to the "Darkness = scary" trope, but there are enough good Darkness beings and evil non-Darkness beings thrown into the mix though that I wouldn't say it's particularly imbalanced outside of the ShadowScythe's involvement.