The NightWing tunnels, also referred to as "portals" in the series, were passages created by the NightWing animus Stonemover. They were used by the NightWings to make traveling from one essential location to multiple other locations easier. There are currently two known tunnels, one leading to the NightWing island, the other leading to the Kingdom of Sand; both tunnels had one side in the Rainforest Kingdom.
On the outside of the rainforest tunnels, a small waterfall splashed into a tiny pond. A stream no wider than a dragon tail burbled at the top of a waterfall and away from the pond at the bottom. Thick brownish reeds choked the slimy surface of the pond. The top of the waterfall was flanked by a pair of tall dark trees, as fat around as the columns where SkyWing prisoners were kept. Their trunks were so brown that they were nearly black, and their branches began far overhead, so they looked more like black pillars than trees. The closest one had a boulder leaning up against it that was twice the size of Morrowseer. The hole to the tunnel is dark, with stone edges, and just big enough or a full-grown dragon to pass through. A moss curtain partly covered it. A faint wind whistled out of the hole, like a storm howling on the far side of the world.
The first tunnel was in a boulder; the second was in a tree on the other side of the stream. One cannot easily notice the hole if they haven't been looking for it, as it was well above eye level, carved into the tree at a height where most dragons would have to look up to see it. The tunnel on the Kingdom of Sand's side was surrounded by a semicircle of dull green cacti. Each cactus was half as tall as a full-grown dragon, with tiny thorns as sharp as fangs. A few dusty white flowers bloomed between the freckles. The wind covers the hole with new sand everyday, blocking and hiding the entrance.
The walls inside the tunnels were long, and was all smooth stone. There were many abrupt turns inside the tunnels. The tunnels gives those passing through an indefinably uncomfortable, tingling feeling in their scales when they are near, described as an "awkward wrongness" or the feeling of when one is not supposed to be there. This, however, may possibly just be the a result of animus magic.
After the events of The Dark Secret, a layer of ash covers the floor, and the space is so dark that it is nearly impossible to see, with faint gray light scraping the walls on either side. The huge shape of Morrowseer's corpse looms overhead, its wings outstretched and its talons reaching forward. Around the body, there is a tunnel clogged up with ash that an average-sized dragon could barely squeeze into, and a floor of cooled lava that is still warm.
The original purpose of the tunnels was to help NightWings (and potentially extra SandWing forces) make traveling quicker between mainlands, specifically between the rainforest and the volcanic island. The tunnel connecting the NightWing island to the Rainforest Kingdom was intended to be a passageway for the NightWings to arrive immediately at the rainforest, either for hunting or a potential takeover invasion. The tunnel connecting the Rainforest Kingdom to the Kingdom of Sand was created so that Blister's forces could arrive as backup for the NightWings during the takeover.
The tunnels were created by Stonemover approximately two years before the dragonets of destiny hatched. Shortly after the dragonets of destiny were introduced to the RainWing village, they discovered a strange tunnel inside a boulder, curtained with moss and leading to a location just miles away from Burn's stronghold.
When the NightWings captured Glory and fourteen other RainWings, they were taken through another tunnel in a tree that leads to the NightWing island. She eventually escaped the NightWings with the help of Clay and Deathbringer via the Rainforest-NightWing island tunnel. Later, she led her army through this tunnel to the NightWing island. Both tunnels are presently still intact.
After Stonemover made them, however, he flew away to Jade Mountain to live the rest of his days as a hermit without using any of his powers and turned the loss of soul into a loss of scales, resulting in about half of his body becoming cold, unmovable stone.
- The tunnels give off a weird sensation, as if one wasn't supposed to be there; This sensation grows stronger as one steps farther into the tunnels. This was most likely another part of the enchantment so that no other dragons would want to look into it. This could also be from the animus magic on its own.