Kurt is one of several new characters introduced in Ghost Smile D.I.Y.. He has been confirmed to be a major protagonist in the upcoming Ghost Smile 3.
A good deal of Kurt's history was revealed in his interview in Ghost Smile D.I.Y. According to the interview, he was named after Nirvana frontman Kurt Cobain, and was raised by "cool punk rock parents". He and his parents were killed by one of Mythic's human minions. Kurt's parents, having fulfilled their destiny, went to Heaven, though Kurt himself remained as a ghost. His destiny was to make some really good music, which he quickly fulfilled, but he decided to stay as a ghost until he could avenge his parents and defeat Mythic. He became obsessed with achieving this goal, remaining as a ghost for several thousand years. Far into the future, he was present when Mythic stole a recently-invented time machine, known as the Time Capsule, from the Greys. He hitched a ride as Mythic escaped into the past with the machine. He landed in the present day, quickly making an ally of Smile, who became one of his closest friends and joined him on his quest to defeat Mythic.
Kurt, being a music geek, references various bands multiple times:
Ghost Smile D.I.Y.
He wears an Avenged Sevenfold t-shirt in his interview.
His car is a silver pickup truck, a reference to his favorite band, the Silversun Pickups.
His car has a bumper sticker of the Radiohead bear.