Cassandra Gava played the witch. Milius hired more than 1,500 extras in Spain. Professional actors from the European film industry were also hired: Valerie Quennessen was chosen to play Osric's daughter, Jorge Sanz acted as the nine-year-old version of Conan, and Nadiuska played his mother. The drafting of a story for a "Conan" film started in 1976; Summer conceived a script with the help of Roy Thomas, a comic-book writer and Conan expert who had been writing the character's adventures for years for Marvel Comics. Summer and Thomas's tale, in which Conan would be employed by a "dodgy priest to kill an evil wizard", was largely based on Howard's "Rogues in the House". Their script was abandoned when Oliver Stone joined the project. Stone was, at this time, going through a period of addiction to cocaine and depressants. His screenplay was written under the influence of the drugs and the result was what Milius called a "total drug fever dream", albeit an inspired one. According to Schwarzenegger, Stone completed a draft by early 1978. Taking inspiration from Howard's "Black Colossus" and "A Witch Shall be Born", Stone proposed a story, four hours long, in which the hero champions the defense of a princess's kingdom. Instead of taking place in the distant past, Stone's story was set in a postapocalyptic future where Conan leads an army in a massive battle against a horde of 10,000 mutants. When Milius was appointed as director, he took over the task of writing the screenplay. Although listed as a co-writer, Stone said Milius did not incorporate any of his suggestions into the final story. Milius discarded the latter half of Stone's story. He retained several scenes from the first half, such as Conan's crucifixion ordeal, which was taken straight out of "A Witch Shall be Born", and the climbing of the Tower of Serpents, which was derived from "The Tower of the Elephant". One of Milius' original changes was to extend Stone's brief exposition of Conan's youth—the raid on the Cimmerian village—into his teens with the barbarian's enslavement at the Wheel of Pain and training as a gladiator. Milius also added ideas gleaned from other films. The Japanese supernatural tale of "Hoichi the Earless", as portrayed in Masaki Kobayashi's "Kwaidan" (1965), inspired the painting of symbols on Conan's body and the swarm of ghosts during the barbarian's resurrection, and Akira Kurosawa's "Seven Samurai" (1954) influenced Milius' vision of Conan's final battle against Doom's men.