Jack Kline

Jack is the son of Lucifer (Supernatural) and a human woman. He is a Nephilim in the CW's hit-tv series Supernatural.

Season 13
After his birth, Jack wandered around to find his father stating his biological father Lucifer wasn't him but his uncle Castiel was.

Jack overheard the argument and sadly said Castiel's name, with his eyes glowing in the process. Jack's voice telepathically reached The Empty where the soul of Castiel was sleeping before he awakes hearing Jack calling his name.

Jack helped the brothers in a case with a shape-shifter and has the good one help him get closure for his mother's passing and soon uses his powers to save Sam from the shifter who was planning to kill everyone. He is given approval from Dean and takes it with a smile.

While the Winchesters are out on a case, Jack stays at the Bunker on the computer doing research. When they return, they bring a surprise it is a resurrected Castiel who returned because Jack awoke him. Castiel was relieved to have him back and hugged him.