Joseph Delaney, author of the Spook’s fantasy book series, has died aged 77, his family has said.

He died on August 16 “after an illness, which, in his indomitable style, he kept to himself and his family so he could carry on with writing as much as he possibly could”, a statement from publisher Penguin Random House on behalf on the family said.

His first book, The Spook’s Apprentice, was published in 2004 and later adapted into the 2014 film Seventh Son, which starred Ben Barnes, Jeff Bridges and Julianne Moore.

His children – Joanne, Paul and Stephen – said in a statement: “Dad loved writing and lived his dream over the last 18 years as an author published by Random House and Penguin.

“His imagination was boundless, and he could have kept creating new and exciting stories for years to come. He enjoyed meeting fans throughout the world and hearing their thoughts on his books.

“We are very proud of what he achieved. There is a great deal of Dad in his writing, and we see that in every page.

“When we were young children, Dad would tell us very scary stories that should not have been told after dark! We are so fortunate to have those memories.”

They remembered him as a “a wonderful dad and a deeply caring man with an infectious sense of humour, especially after a glass of red wine”.

Their statement concluded: “We hope that his books will inspire children and adults to create stories and live dreams of their own. That would have made him happy.

“We would like to thank Penguin Random House as well as all the wonderful people who helped him on his adventure, and especially everyone who has read his books.”

After the success of The Spook’s Apprentice, Delaney left his job as an English teacher and went on to write 12 more titles in the best-selling dark fantasy series The Wardstone Chronicles.

He wrote another 17 books predominantly set in the same world. The books have been translated into 30 languages and won a number of prizes, including the Lancashire Book Award.

His books have sold more than 4.5 million copies around the world.

Ruth Knowles, publishing director for Puffin, said: “The Spook’s Apprentice was first published just before I joined Random House Children’s Books (now Penguin Random House Children’s) and so Joe and his totally unique blend of fantasy-horror have been a part of my entire working life.

“I was so proud to have been his editor for many years.

“It was frustrating at times – we would meet for a beer in Manchester, and in response to my questions he would simply smile and remind me every time that he followed ‘The Bram Stoker’ method of writing (meaning nothing was ever planned or plotted in advance!) so I would have to wait for answers – but it was also, of course, completely magical as the creatures and characters from his worlds would slowly come into focus, journeying into brilliantly terrifying adventures.

“I hope he’s with the ghosts of his beloved Lancashire now and that there’s some delicious red wine on tap. We are so very proud to publish him.”

Delaney is survived by his second wife, Rani, his two sons and daughter, and his grandchildren.