I have a question to the Tolkien-savvy people out there:

Wargs, vampire bats and attercops are malicious beyond natural brutality; they are even smart enough to have a language of their own and presumably have a greater sentience than their "natural" counterparts.

But what of regular wolves, bats and spiders? Are there any "uncorrupted" wolves and bat left in the world? Are they associated to evil because they are under the long influence and corruption or Morgoth?

In other word, is the wolf/bat/spider mythologically evil, or not but perceived as such by the free people of Middle Earth, or can people easily make the difference between evil wolf (warg) and wild (and therefore sometimes dangerous) wolf?

The jist of "Morgoth's Ring" is that his "Ring" (ie, his equivalent of the One Ring) was in fact the whole of Arda; all of physical creation. His malice poured out into all the world and affects all physical things. Tolkien being a Catholic, this is his equivalent of original sin, if you will.

I have never seen anything though to suggest that Wolves, Bats or Spiders exist outside the natural order of things (aka, the song of the ainur) and have no intrinsic evil past whatever malice is in Arda as a legacy of Morgoth's will.

If people (free or otherwise) fear the natural savagery or power of those things, and/or likewise if agents of the shadow revere said savagery/brutality, then those are psychological projections that fall on their shoulders, and are just further testimony of Morgoth's perversion (unjustified fear and/or misplaced reverence for savagery). A wolf is a wolf and has just as much right to hunt and eat and be in concert with the song of the Ainur as an elk.

Here's a couple of quick though awkward examples that may help:

'It is as I feared,' said Gandalf [following the Fellowship of the Ring's battle with the Wargs in Eregion]. 'These were no ordinary wolves hunting for food in the wilderness...'

Mind, he'd just confronted the 'Hound of Sauron' (Hmm, where have we heard this term before?) , but it's a good indicator of the difference between the two extremes.

Also note the effect on the 'beast spell-enslaved' at the final battle at the Morannon when Sauron fell.

I think we have to differentiate between normal animals and evil emboided spirits.

- Wargs seem to be the offspring of the First Age Lycanthropes, which were lesser evil Maiar incarnated in the form of great wolves. Same as Melian took the form of an Elf and has a daughter with an Elf, incarnated spirits can have offspring.

- Giant evil spiders of Mirkwood are the offspring of Shelob.

- Giant bats could be related with First Age Vampires.

So, same as the Mearas are not the same as a regular horses, or the Great Eagles are not just eagles, there are evil and good beings in animal form in Middle-earth. I'm not saying all of them must have Maiar origin, but if they haven't at least they have been "blessed" (coming from Aman) or "cursed" by the Valar.

And then, of course, we have normal animals working for good or evil like the crebain of Saruman.

Animals were animals. Evil version (and good) did exist - like Wargs or Giant Eagles - and these were "intelligent" as opposed to neutrality of nature.

Though many animals were used as spies for The Shadow (and for good), which may be why they could still be seen as foul.