George RR Martin has been working on the penultimate Game of Thrones book The Winds of Winter for the last 13 years.

Over the past week, the 75-year-old has been more active than usual on his blog, mentioning the upcoming novel in passing.

His most recent post focuses on the dragons as portrayed in A Song of Ice and Fire.

During the essay, the author shared what plot details he plans to reveal in The Winds of Winter and final book, A Dream of Spring.

Martin wrote on his blog: “My dragons do not talk. They are relatively intelligent, but they are still beasts. They bond with men… some men… and the why and how of that, and how it came to be, will eventually be revealed in more detail in THE WINDS OF WINTER and A DREAM OF SPRING and some in BLOOD & FIRE. (Septon Barth got much of it right).”

Blood and Fire will be volume two of Fire and Blood, the 300 year history of Targaryen rule on the Iron Throne. A book Martin says he won’t write until after A Dream of Spring.

Martin added: “Like wolves and bears and lions, dragons can be trained, but never entirely tamed. They will always be dangerous. Some are wilder and more wilful than others.They are individuals, they have personalities… and they often reflect the personalities of their riders, thanks to bond they share are. They do not care a whit about gold or gems, no more than a tiger would. Unless maybe their rider was obsessed with the shiny stuff, and even then…”