The main Night Fae ability is Soulshape. It transforms you into the shape of a creature, and blinks you forward. The blink is on a four second cooldown. You also move faster while in Soulshape form. In the regular world, Soulshape lasts for a few seconds, so it's a temporary speed boost/blink combination. Soulshape is on a 1.5 minute cooldown.
There are many different shapes that you can collect or find. You get two more, stag and moth, through the story. I spent 1500 anima on a tiger shape from the mushroom network NPC. (In hindsight, perhaps not the best use of anima.)
The other interesting element of Soulshape is that if you use it in a rest area, it has an infinite duration. This is especially useful in places where you cannot mount. So you can freely run around Oribos or the Heart of the Forest in Soulshape form and it is faster than walking.
However, one issue with Soulshape is that if you go through a portal, it will pop you out of Soulshape. There are two such portals in the Night Fae headquarters, one to the mushroom network and one to the Queen's Conservatory. It's pretty common to go through the portal, come back out, and still have Soulshape still be on cooldown.
A small quality-of-life improvement would be for Soulshape to have no cooldown if used in a rest area. It already lasts forever, and this would just clean up the few rough spots where you get forced out of Soulshape.