Chase Stein is the son of mad scientists Victor and Janet Stein. The two supposedly made a fortune from inventing a tool that removes stickers from CDs, but were actually members of the secret group of super villains called The Pride. Victor often physically abused Chase for talking back and for getting poor grades in school.

Chase often comes across as being a dumb, obnoxious jock, but he is surprisingly street smart. Before he learned that his parents were members of The Pride, Chase wanted to be an announcer for ESPN, but after his experiences with the Runaways he decided that he wanted to join the FBI to help other troubled teens like him, with the added perk of carrying a gun all the time.

He received his codename "Talkback" from Gertrude's sarcastic remark, and for his habit of talking back. The only Runaway with a driver's license, Chase transports the team in the Leapfrog. He used equipment stolen from his parents, "weaponized" gloves called Fistigons and multi-spectral goggles, but the gauntlets were destroyed in the final battle with the Pride. Chase was the one who originally found the Runaways' first hideout, a "missing mansion" which was swallowed up during an earthquake in the 1920s or 1930s that he nicknamed "The Hostel".