Chip is the youngest member of the Vehicle Voltron. A member of the Air Team, he flies the Advanced Recon Helicopter (#4) that becomes the left upper arm of Voltron.
Voltron: Defender of the Universe continuity
Pidge and Chip are twin brothers and were orphaned at a young age. When his foster parents wanted to adopt Pidge, he refused to go unless they took Chip as well.
Devil's Due comics continuity
When Pidge and Chip met for the first time and deduced they are brothers. 
- The Pidge/Chip relationship was invented for Voltron. Pidge is based on a Beast King Golion character, whereas Chip is based on a Dairugger character. The two Japanese series continuities' are completely unrelated.
- Chip's last name may not be "Stoker" like Pidge.
- In the Voltron: Defender of the Universe cartoon continuity, Pidge and Chip were adopted from an orphanage by the same family, so in that continuity they might share a last name, except that the cartoon didn't provide last names for any Voltron team members (Lion or Vehicle).
- In the DDP comics continuity, Pidge and Chip did not know each other prior to the two Voltron teams' meeting, thus we can assume they did not grow up in the same family, and do not have the same last name.
- In the Voltron: Defender of the Universe episode "A Ghost and Four Keys", Pidge calls himself an "Earth man." In this series' continuity, the brothers were raised together in the same family, thus we can assume that Chip may also self-identify as an Earth-man (though we still don't know where either brother was born, let alone grew up).