Steffon Baratheon (son of Robert II)

Prince Steffon Baratheon was the first child and son of King Robert II Baratheon with his first wife, Queen Tyra Tyrell, the older full-brother of Eddard, Laena and Quentyn Baratheon, and the older half-brother of Cassana, Lyra, Shireen, Ysabel, Gendry, Lyonel, Floris, Martyn, Alynne, Trystane, Rosamund and Rylene Baratheon, Shyra, Adrian and Duncan Waters, Sansa Snow, Durran Storm and Roslin Rivers. He was the heir to the New Throne for his entire life, before passing away in 390 AC, leaving his grandson Edric to inherit the Throne upon his father's death one year later.