who is the third character mentioned here?
Pete was the childhood best friend of Clark Kent in Smallville. One night when they were camping together, Pete secretly saw Clark changing into Superboy to attend to an emergency.
Pete Ross
Pete was the childhood best friend of Clark Kent in Smallville. One night when they were camping together, Pete secretly saw Clark changing into Superboy to attend to an emergency. Pete kept his knowledge of the superhero's secret identity to himself, even avoiding revealing his discovery to Clark. Pete resolved to use this knowledge to help his friend, for example by creating a distraction to allow Clark to slip away from a dangerous situation without raising suspicion.

The Legion of Super-Heroes was aware of Pete's assistance to Clark 
in what episode does chloe find out about clark Season 1 which show is this? "Smallville" what type of show is it? It is an American superhero television series who are the main characters? Clark Kent, Chloe Sullivan, Pete Ross Lex Luthor who is the second character? Chloe is Clark Kent's best friend, Lois Lane's cousin, and the editor of the high school newspaper the "Torch"
wiki:20104889
Pete Ross [SEP] Silver Age
During the Legion's battle with Mordru in "Adventure Comics" #370 ("The Devil's Jury"), it was stated that Pete Ross's knowledge of Superboy's secret identity would one day end up saving Superman's life (explaining why the Legion allowed Pete to retain that knowledge); however, no subsequent Superboy or Superman story featuring Pete Ross, as a teenager or an adult, ever followed up on this detail. As an adult, Pete became a widower with a son named Jonathan, who also learned the secret of Superman's secret identity (as shown in "Action Comics" #457). When Pete's son was kidnapped by an alien race ("DC Comics Presents" #13), Pete revealed to Clark his knowledge of his friend's dual identity, imploring Superman's help.