Samuel “Sam” Alexander better known as Nova is hero from Marvel Comics and one of the Nova Corps.
Sam Alexander is a fifteen-year-old living in Carefree, Arizona with his father, mother, and little sister. His father is a drunk who often talks about his supposed life as a Nova Centurion, and shirks his duties as janitor at his son's school. Sam's mother is Latina and a homemaker. It is hinted throughout the series that Sam's mom knows something about her husband's previous, heroic lifestyle. When Sam comes home from school to find his father missing, Sam accidentally injures himself and wakes up in a hospital. There, he is greeted by Rocket Raccoon and Gamora, who reveal Sam's father really was in the Nova Corps. After putting on the helmet, Sam travels to the moon, meeting Uatu the Watcher, who reveals a fleet of ships. Upon returning to Earth he reunites with Rocket Raccoon and Gamora, who train and tell him to scout the Chitauri fleet. Sometime later, Sam has become a Nova before the Avengers vs. X-Men storyline. He is on a mission to warn planets in the path of the Phoenix it is coming. He crashes on Earth, but is able to deliver the warning.
After recovering, Nova joins the Avengers and the X-Men against Cyclops, who has become the Dark Phoenix. Thor then asks if Sam will join the Avengers.
On his way home, Sam is ambushed by Diamondhead. Sam defeats Diamondhead by luck, and leaves the villain stranded in the desert.
During the "Original Sin" storyline, Sam Alexander begins to reflect on his superhero career. Sam goes for another day of training with Uatu the Watcher at the Watcher's moon base. Stumbling around the place, he ends up finding Uatu's weapons storage. Sam asks about some of them and Uatu gives him the origin story of the Watchers. He even shows Sam what he watches in the Multiverse all of it using his Nova helmet. Sam also learns that Uatu's father was the Watcher who originally gave nuclear technology to the Prosilicans. Uatu's search of parallel universes is motivated by the desire to find the one world where his father's act of charity was proved to be the right thing to do. Uatu also reveals that his father Jesse Alexander is alive. Sam leaves, happy.
And he is reprised by Logan Miller in the English dub and Hisayoshi Suganuma in the Japanese dub.