Marty is the Neo-Martian, a powerful Mars People created by Rootmars. It was originally a normal Mars People with no special traits, but a burning desire to protect others from harm despite being weak.

He is very good friends with the Professor, and although it had a rough start with Percier, also checks on her well-being. 
He usually says "Beep Bep" at the outside but when he speaks English usually inside the (Box here) as he is martian as he speaks their martian language. 