Fin has a secret; one that can not be shared.
He has an undying love for fire. He craves the heat and only feels at peace when he's engulfed in flames. His skin never blisters or shows the slightest sign of discomfort when he sneaks off into the woods to feed his addiction.
It's only when the cold sets in that he feel an aching pain in his chest. Fin can't let anyone find out. Others, who were different like himself, have been burned alive when they were discovered.
A small part of him wants them to, just so he can know what it's like to be surrounded by fire.