Skuld is one of the three Norns or Fates of Norse mythology, who sit beneath the great ash-tree Yggdrasil and spin the thread of destiny.

Yggdrasil is the World-tree of Norse mythos, representing the Axis Mundi (axis of the world) or Divine Center, and the Tree stretches from the Underworld to the Heavens, connecting all the Nine Worlds. Though an ash, Yggdrasil is evergreen, symbolizing its strength and changelessness, and the ash's habit of dropping its leaves in autumn while still green--i.e. they don't fade or change color--may have influenced the choice of tree.

Yggdrasil has three great roots that connect with different realms, and each have a corresponding sacred spring. The first root reaches to Niflhel, the Underworld, over which the Goddess Hel presides, and the spring is called Hvergelmir, the source of the primordial rivers. The second root connects with the land of the frost giants, Jotenheim, and the spring that rises there is called Mimir, the Well of Wisdom. The third root finds its way to the heavens, and its spring is that of the Norns. The spring is named Urd after the wisest and eldest sister, and They use it to water Yggdrasil.

The Norns are originally from the land of the Giants. Their names are Urd or Urdi ("Fate", or "That Which Was", the Norn of the Past), Verdandi or Verthandi ("Present" or "That Which is Becoming", from the same verb as Urdi's name) and Skuld ("Shall-be", or "She Who is Becoming"). They represent inexorable Fate--men and gods alike are bound by their pronouncements. It is likely that originally there was only one, Urdi, whose name is cognate with the Anglo-Saxon wyrd, a word which became English "weird", still used as an archaic word for "fate". Later Verdandi and Skuld were added, perhaps through influence of the Greek triple Moerae or Fates.

It is said that the two eldest Norns set happy fortunes for people, while Skuld, the youngest, often changes their decrees to more tragic outcomes. Skuld as the last of the three is the Norn who fixes the length of the thread of life, or, by some accounts, unravels what Her sisters have made. She is shown veiled, as the future is unknowable. She is sometimes considered a water spirit or even a Valkyrie, one of the swan-maidens who foretell the destiny of warriors (the word valkyrja means "she who chooses warriors destined to die in battle"). She rides out with the Valkyries Gunnr and Róta to choose who shall be killed.

The Norns tend to Yggdrasil, watering it and keeping it healthy. Though four stags (with the Tolkien-y names of Dáin, Dvalin, Duneyr and Durathrór) are always nibbling at Yggdrasil's buds and new leaf-shoots, the Norns keep it green and growing.

This card in a reading indicates uncertainty and the unknowable future. Some things you just have to wait for; though sensible preparation is always a good idea, sometimes you just can't tell what is coming next.