SOLVED. Fantasy book set in forest, also murderers [s]

[Yamnaa]

I remember the cover being very flamboyant, and I read this about 5 years ago.
Okay so this book is set in a forest, most of the time. The narrative is non-linear and involves a man, and a youngish girl and one more character, a robot.
The man has back-story that he was trained as a child, along with a group of other children to be killers. His trained can kill telepathically and their captors/handlers I Think are called Regents, or Regals.
There is a scene in which one of the children dies in severe pain from appendicitis, and the handlers are very angry they were not alerted.
There is a girlchild that the man, when he is there, looks after. She cannot bear to kill so he kills for her 'regal/regent style' with his mind to make it seem she is doing it.
They get caught and there is a scene of the handler washing his hands, I think, as the girl lies 'faintly screaming.'
There is another scene, in the forest with the girl in the forest, and the man, grown up, that involves him snapping the neck of a rabbit in pain without even looking down to see. The girl is horrified by this.
At the climax of the story, it is revealed the man was supposed to procreate with the girl in the forest, and produce more killers. The Robot is revealed to be some hugely important character.
Well that's all I remember, thanks in advance for helping out!

[Mir]

I'm pretty sure this is Diana Wynne Jones' Hexwood. Does it open with a girl recovering from illness and then going to the woods?

[Lou]

I second hexwood. I just finished it today, and it fits very well.

[Yamnaa]

I think it is thanks so much ^^

[Ann aka Iftcan]

Yamnaa, do you want to call this solved or wait until you can check out the book?

[Yamnaa]

i'll call it solved, thanks