The book or books I read maybe 30 years ago we’re about a boy who is taken into a guild and learns the basics of magic, but there are different guilds with secrets which all take a lifetime to advance to being a master. He leaves the guild and joins another , he realises that he can combine the magics of the different guilds to be more powerful than the wizards. I also think this book contained a plot than involved demons and imps that could get into the world through fires if they could capture the gaze of a person staring into the flames ( or maybe that was another book 
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please if anyone has any ideas on the author or books that would be great
)please if anyone has any ideas on the author or books that would be great
