No one wants them and they are treated like lepers because of the fire that burns through them. Bugs are dangerous and often killed when fire appears in their palms during their infant years. They are thought to be people who suffer from an illness of flames and are considered highly dangerous due to their inability to control it.
Jak is one such bug. While most would have disposed of a newborn who showed the sickness, his parents hadn't. They allowed him to live until they were unable to handle him any longer. It had hurt when he was thrown out at the tender age of six, but when a young man finds him and promises a new chance at life... and the possibility to learn control over his fire, he hesitantly accepts the offer.
Because of the kindness that man had showed him on that one fateful day, Jak survives... and thrives. By the time he is in his early twenties he had rescued many young bugs who would have faced death anywhere else. But he's sick of just saving them. He wants to do more. To be able to banish the kill order that had been in place for several years for the poor fire-children. It is a dream considering his current situation, but dreams keep the spirit alive. And his burns like a raging fire.