SOLVED. YA or Children’s Fantasy book. I remember a few bits from a book I read as a child but I haven’t been able to remember the rest of the book or find it.

[Mark]

I think the book had a boy or two brothers who went into a alternate world I think there was a island with fairies on it somewhere in the world and a black fairy who was involved in the worlds politics somehow and the world was in the middle of a major war and one of the sides was on the brink of a technological revolution. I think the main character was poisoned or cursed by the black fairy at some point.

[Mark]

Found it, the book I trying to remember was reckless.

[Mark]

By Cornelia Funke