The Fae, they are called, though the reason they are not called by their true name, the Fairies, has been lost to the ages- at least, by the humans. The other races know, the other races know well of the Fae.
Humans have a very short memory. The elves, the dwarves, the goblins, the orcs, they don't. They remember of the interactions between Atheians and the Fae all those years ago in that other age. They know what happened. But the humans... they have forgotten.
This is why they will be the first to die.
A war of ambition threatens the unseelie houses of Thiran Nar.
The blade of the adamant blossom…
On a location with numerous webs, and at least one big spider, there is a something inside a cocoon. It is humanoid in shape, still moving. If the heroes free it (not before they kill or drive away the spiders), they meet a ... zombie!
The poor zombie wandered the dungeon alone, and tried to kill a big living creature (= a spider). The spider used the usual treatment, even if this victim did not look tasty. The zombie can be easily killed as any other zombie. It got but several doses of spider-poison, so can be something worth if it is extracted. You can mention to a druid or ranger the fact the spider had no poison anymore.