"This goes deeper than you think..."
Vurus to Erik Dragen
The Red Dragon prophecy is an ancient Asshai'i prophecy foretold by the Red Priests of the Lord of Light clergy. According to this prophecy, a series of tragic events will occur which will set in motion a - currently unknown - major event that could alter Westeros indefinitely. This prophecy is a major plot point in the fanfiction trilogy Demon of the North.

Prophecy of the Red Dragon

The three catalysts

The Three Catalysts (click to expand).

The Prophecy of the Red Dragon is said to originate thousands of years ago in the Shadow Lands beyond Asshai. According to the prophecy, the ancient, evil warrior Vyrio Ahai returns from the dead and reincarnates as the Red Dragon, a tormented soul who kills and eats his enemies. The Red Dragon, also called the "Lord of the Hunt", who is born as the eldest child of the "Father of the Dead", cooperates with an individual known as the "Prince of the Moths", but later betrays the "Prince" to achieve their own personal goals. If not stopped, the "Lord" will cause major damage and chaos for the continent of Westeros. These three individuals are commonly referred to as "The Three Catalysts".

The prophecy itself can be read here, in English:

A child, born amidst snow and darkness
Sired from the Father of the Dead
Will pave the way for Evil
As the Lord of the Hunt
As the child grows older
His desire to kill grows
When he betrays the Prince of the Moths
He will foresee his own undoing
The child, the Red Dragon
Vyrio Ahai.

In Wastelandic:

Kiir, kiin benix od ahrk vulom
Zoh nol faal Bormah do faal Dilon
Fen baar ven fah Vokul
Ol faal Drog do faal Nir
Ol kiir naram zuwuth
Ok tolaan wah krii naram
Fod rok grut faal Kulaan do faal Rak
Rok fen promiin ok vo
kiir, faal Sahqo Dovaar
Ahai do Vyrí