How do you feel about a character who's back story includes being reincarnated into their current race?
He's not done yet but that's the plan for Grimsby here, originally came from the area where the players are now, but after being killed and reincarnated during an outing to another country, he became a goblin.
His family already disliked him, hailing from a lineage of fighters and warriors his Wizardry was seen as dishonorable, despite his clear nack for the craft. Hes been fully estranged now that he is no longer human, worst thing he could have turned into honestly... He's vermin far as he and his family see it. Wanting to get away from his family and all the people he knows will be the motivation for coming along with the party, maybe his craft will allow people to see him as more than a weak rat somewhere else in the world.