toriyama originally created krillin along with the tenka'ichi budōkai as a method to help add depth to the story, as his editor kazuhiko torishima had stated that the series' protagonist, goku, was too plain. torishima explained that in order to develop goku's characterization, they needed someone petty and mischievous to provide contrast, thus leading to the introduction of krillin. yūsuke watanabe, who wrote the screenplay for the film "", had originally written the film to take place at krillin and android #18's wedding, but toriyama wrote it to take place at bulma's birthday party. watanabe thought toriyama made the change because he wanted fans to imagine the wedding for themselves. toriyama cited krillin and bulma's older ages at the end of the manga as a reason he chose for "battle of gods" to take place after the boo arc since they were in their "strongest condition at that time."