Great Rune of the Unborn
The Great Rune held by Rennala, Queen of the Full Moon, in the form of an amber egg. Unlike other Great Runes, it does not need a Divine Tower: it works from the start.
What it does in practice is let Rennala offer rebirth. You can change your appearance for free, and reassign your attributes by spending a Larval Tear.
Item description & lore
The amber egg holds the Great Rune of unborn demigods. Rennala uses it to give new birth to others, but the children she creates this way are fragile and do not live long, each one imperfect.
The egg was a gift from Radagon when he left Rennala to become Elden Lord. It is not clear whether the Great Rune came with it or was drawn to the unborn demigod inside the egg after the Shattering.