Kid Danger is played by Jace Norman.
The specifics of his origins are unknown save that he was recruited to be the sidekick to the superhero Captain Man based on his wits and ability to create useful gadgets.
Henry Hart is the son of Jack and Siren Hart and was raised with his sister Piper. It is unknown if he was born in Swellview but he currently resides there with his family. At some point, he made an impression on Captain Man, a superhero of the city of Swellview.