Dragon Ball: Sleeping Princess in Devil’s Castle

Roshi uses the legend of the Sleeping Princess as a practical entrance exam. He wants students who can handle real danger and prove their worth through action rather than just words. The quest tests both combat ability and character, whether the applicants will work together and make moral choices under pressure. Whoever succeeds demonstrates they have the potential for serious martial arts training.

Earlier, Roshi is shown distracted by training videos, suggesting he takes his role as a teacher seriously but wants students who can meet high standards.

Goku transforms into a Great Ape, a massive golden-haired giant with immense power. This happens because Goku is a Saiyan, and Saiyans gain this transformation when exposed to the light of a full moon. The Great Ape form multiplies his strength dramatically, but he loses his normal intelligence and goes on a rampage. In this movie, the moonlight passes through the Sleeping Princess, amplifying its power and triggering Goku's transformation.

The full moon night is established earlier as the ogres prepare their ceremony.

While Goku in Great Ape form smashes through the rock barrier freeing the group, Yamcha and Krillin grab his tail to restrain him. Puar then transforms into scissors and cuts off the tail. Without the tail, Goku reverts to his normal human form. However, Goku doesn't remember anything about the rampage afterward, he simply wakes up confused to find his tail is gone.

The danger of the Great Ape transformation is set up when the full moon appears and Goku starts growling ominously.

Launch is cursed with a magical condition that causes her personality to flip based on sneezing. When she sneezes, she transforms from her good-natured blonde self into a blue-haired hardhearted version. The curse is permanent and has no known cure. This is played for comedy throughout the movie, she briefly turns aggressive against her friends, then sneezes again to revert to her kind self.

Launch is introduced as impulsive and competitive, but her later personality flip comes as a surprise the first time it happens.

Lucifer's plan requires fresh blood to awaken the Sleeping Princess, who lies in a magical coma. The vampire-like count explains that draining Bulma's blood will provide the life force needed to break the princess's sleep and activate her latent power. This dark ritual is what drives the villains' actions throughout the movie and creates urgency for the heroes to rescue Bulma.

Lucifer and Igor are introduced as sinister figures from the start, with their true nature revealed when they bind Bulma with vines.

Lucifer places the Sleeping Princess inside a massive laser cannon, using her amplified power from the full moon to fire a destructive beam at the rising sun. The princess serves as the energy source for this weapon, the same moonlight that triggered Goku's transformation has charged her with enough power to attempt destroying the sun itself. Goku's Kamehameha damages the cannon's core, causing the castle to collapse.

The full moon earlier powers the princess to awaken, establishing her as a source of immense energy.

Oolong uses his shapeshifting ability to transform Yamcha and Puar into ogres so they can infiltrate the castle and rescue Bulma. However, the transformation has a strict five-minute time limit. Once those five minutes pass, Oolong's illusion wears off, and Yamcha and Puar revert to their true forms in front of the ogres, immediately exposing the rescue attempt and leading to their capture.

Oolong's shapeshifting is established earlier as a useful but unreliable power with time limitations.

When Goku's Kamehameha shatters the cannon and the castle collapses, the Sleeping Princess vanishes into the dawn. She is not recovered by any of the characters, in fact, her ultimate fate is left unclear. The heroes succeed in stopping Lucifer's scheme and saving Bulma, but the princess herself disappears as the Devil's Hand is destroyed, her power seemingly returned to wherever it came from.

The prophecy earlier stated that whoever frees the Sleeping Princess earns training, but the heroes' victory comes from stopping Lucifer rather than rescuing her.

Krillin feels guilty because he previously showed jealousy and competitiveness toward Goku during the quest. Rather than fully supporting his friend, Krillin let his desire to become Roshi's student create tension between them. After seeing Goku risk his life to save him from Lucifer's ogres and take a vicious beating, Krillin recognizes his own selfishness and feels genuine remorse for not being a better friend.

Krillin's competitive attitude is shown early when he bribes Roshi and tries to outdo Goku.

Even though Launch creates trouble by stealing the princess and briefly turning into her aggressive personality to fire at everyone, Roshi still accepts her into his training program. This reflects Roshi's character, he sees potential in anyone willing to train hard and pursue martial arts mastery. Plus, Launch actually helped defeat Lucifer by pursuing the princess, so her actions contributed to the overall success.

Roshi's willingness to take on unusual students is established when he accepts Krillin despite his strange bribe.