Long ago, a small sect of fey, ancestors to the current gmone race, agreed to mix their heritage with a group of celestials, so their bloodlines ran intermingled. These fey were ostrasized by their brethren for this, and eventually they died out, and the bloodline went dormant.
Recently after the events of the Darkfall, this bloodline has resurfaced amongst the gnomes. Due to the past history of this bloodline, any gnome found with this bloodline was exiled...which is what happened to Nishalerau Al'Blen.
In truth, fear of what he represents is probably the true reason...at least that is what I tell myself. Sill, being free to wander Golarion is not a terrible fate...
But, sometimes late at night, just before drifting off to sleep...visions of a great evil coming appear, and then is quickly forgotten...most everyone he has talked to about this vision, thinks it refers to the Whispering Tyrant, but he is not so sure.
Now, after wandering for many years, including a couple of years with a Pathfinder member who he became close with before the unfortunate incident.
Where he ended up believing the fey lady, and then allowing his friends betrayal at the hands of her and her 'friends'. Nish renounced her after finding out about the affair and rescued him, an act which nearly cost Nish his own life. He never found out how Nish had been involved, and after the rescue, he thanked Nish with the gift.
Wracked by guilt after what happened he fled the civilized lands, and now he finds himself working with a group of like minded people as a "specialist/scout", at least according to Watch-Captain Alfrik Gundarstein, in the Lastwall region. He feels there is a great evil approaching and needs to increase his control over the bloodline gifts, in order to meet the oncoming threat (and also to atone for his own failure).
Now after having dealt with that threat, he now spends his time wandering the lands looking for new challenges and also people in need to assist...