Umbra
Umbra is one of the restless dead raised with no body at all. It is the natives' dead, stranded at the threshold of the Deep since the Breaking, called up by Umbra where the threshold presses close to the ground. A mage calls it with Summon umbra. This craft, like every raising, goes back to Odrin Half-Core in the Age of Odrin.
Its bond is shallow, and its master can release its borrowed life and dismiss it. The Sealborn say it holds that life only by feeding in battle, taking it from what it touches. Between fights, mana alone keeps it, and it draws no folk from the kingdom.
Blades and arrows pass through it. Magic, fire and holy light do not, and the Sealborn say holy light cuts it deepest.
It keeps no form across Turnings. When it is unmade, what is left of it falls back to the threshold.