In the 1963 series Big Titan is built by an Indian man named Doctor Buck, who wants revenge for losing his daughter in a missile strike, and revenge on Astro Boy for destroying his Robot Chief, who kidnapped Astro Girl, who Doctor Buck mistakes for his long-lost daughter.
Big Titan highly resembles Pluto, even having 1 million horsepower, though he isn't.
Big Titan also appears on the cover of the second Ultra Box Set of Astro Boy DVDs.