Many of the beasts of Theras were created with a purpose – or at least as an experiment – and the Arcane Wyrm is a particularly unique one. Unlike creatures built to extend her areas of control, protect hidden lore, or assist in her research, the Arcane Wyrm was designed to be… a writing utensil. Dissatisfied with being confined to solid materials for her leyscript and rune work, notably when it came to warding and altering locations that consisted primarily of fluid or air (the oceans have been particularly irritating to her due to being almost entirely composed of unworkable surfaces), the Lady of Lore devised a creature that could inscribe any space it traversed: the Arcane Wyrm.
Capable of searing arcane lettering into the underlying weave of reality, this wyrm’s passage can be used to inscribe spellwork on sky and water alike, and Theras ensured it was clever enough to fully understand the nature of its talent and how best to use it. These traits have made it an exceedingly dangerous creature – a beast capable of wielding raw arcane might in any environment with a staggering degree of skill and intelligence.