Constantine is the secondary antagonist Robotboy and is Dr. Kamikazi's henchman, he was born in Japan.
"Dr. Kamikazi’s number one henchman is Constantine. This giant may look threatening but really he’s a very gentle, sensitive sort of villain who enjoys cooking. Constantine mainly keeps Dr. Kamikazi company in his quest for world domination."
He has a high level of physical strength, and is also skilled in Sumo wrestling. He spent his early years in an orphanage, until he was adopted and raised by Kamikazi. Unlike Kamikazi, he is generally not at all an evil person, and has shown himself to be very caring towards other people, and animals as well. He is also somewhat friendly towards Tommy and his friends at times, despite them being 'enemies'. He is also a dedicated chef at times, whenever he cooks for Kamikazi - especially Tapas (and some other Spanish foods) - and when he became the replacement chef for the school cafeteria.
- In the episode "Metal Monster", it was revealed that he can speak Spanish. It is possible that he might have learned how to speak Spanish by learning how to make Spanish cuisine, such as Tapas and Gazpacho.
- In the episode "Human Fist On Ice", he wears Sumo clothes, but Robotboy strips him naked, which prompts him to run after Robotboy, while covering his unmentionables.
- Constantine has been able to catch Robotboy by himself about 3 times in the following episodes: "Constantine Rising", "Cast Iron Constantine" and "Zap! You're Old".
- Of all the episodes in the series, Constantine - along with Doctor Kamikazi - have both appeared in approximately 57 episodes.
- "The Babysitter" is the only episode in which he appears without speaking or making any sounds.
- Interestingly, Constantine has never appeared in an episode by himself without Dr. Kamikazi.
- In the episodes "The Consultant" and "Knockoffs", he gets fired by Dr. Kamikazi, although he gets reinstated at the end.
- In "Momma's Boy", Mother Kamikazi mistakes Constantine for a woman. It may be due to his highly feminine voice, or his love for cooking, or the fact that he has a ponytail.
|Swedish||Dick Rune Eriksson|
|Castilian Spanish||Francisco Javier Martínez|
|Latin Spanish||Rubén León (1st voice)
Óscar Flores (2nd voice)
|Polish||Jacek Kawalec (1st voice)
Janusz Zadura (2nd voice)
- Dick Rune Eriksson is famous for voicing many various cartoons in Sweden including as the voice of Ash Ketchum from the Pokémon series.
- In the Dutch dub of Robotboy, Constantine's name is pronounced as Constantijn. This because he is named after Prince Constantijn of the Netherlands. This could be easily done because Constantine and Constantijn are almost pronounced the same. Only his name and that of Vance Cosgrove are being translated in the Dutch dub, all the others characters have their original English names.
The Robotboy Wiki has a collection of images and media related to Constantine.