Questions are roughly translated and answers are mostly paraphrased. I've skipped some questions that I didn't feel were important. For the author's interview in the movie pamphlet, see here
This interview does have movie spoilers for those who want to avoid them
Part 1[]
"It's been 6 years since DanMachi was first released (January 15, 2013), but what has the series become to you?"
Oomori makes a joke that it's supporting his life, but then becomes serious and hopes that he'll be able to continue DanMachi in various ways once the main series and spinoff end. Whether it keeps on selling or not, DanMachi would the most special series to him
"What did you think when your most special series became an anime then a movie?"
Oomori had been watching the movies of other light novels and had an idea for a movie before the offer came. When the offer came, he was really happy, and felt like "Yes! I'll do my best!"
"Tell me how the movie became an anime original story and how you came to write the script for it"
They initially discussed making an OVA but it ended up becoming a discussion about making a movie with an original story, so he asked via GA Bunko if they'd let him write it. The reason he decided to write it instead of using a scriptwriter like the anime was because it was an original story, therefore it might be hard for other people to get the characters or nuances right, but he also mentions that he wanted to do it. He suggested using the idea he had (from above question) but they told him that it'd be too long and rejected it
"So your plot and the finished movie are completely different?"
The author confirms this and reveals that the original plot involved the Hestia and Loki Familias teaming up to fight a strong monster in the dungeon, but they told him that it "had too many characters" and "would be too long to fit". He realized this and came up with a "protagonist does his best to save the heroine" story. When he thought about what kind of expression the girl would have at the end, an image of the scene appeared in his mind. He came up with the main points of the movie in around 2 weeks
"Tell me what kind of orders the producer and staff gave"
They wanted Hestia to be emphasized and for her to be main heroine, though Oomori refused
"The Goddess Hestia was popular in the TV anime, so why did you refuse?"
Since it'd be an original story, there were plans to have an original character appear, so he wanted said character to be the heroine
"Indeed, the existence of a movie original new heroine would help create a new story, but they end up not being noticed as much"
Oomori agreed and convinced the movie staff, and ultimately they decided to have both of them (Hestia and Artemis) stand out. The author believes that triangle between Bell, Hestia, and Artemis functioned well in the movie.
"That being said, wouldn't it be hard to work with two heroines? In the novel, when a new heroine appears, Hestia isn't as prominent"
"Like you said, Hestia's screentime lessens every time a new heroine appears in the novel, and she can't go with them to the dungeon...". Despite this, he managed to get rid of that concern for the movie. Other than Hestia and Artemis, a lot of other characters play a part in the story, so the author believes that fans will enjoy the movie
"How was the character Artemis created?"
"When I first decided on writing a story where the protagonist saves the heroine, I hadn't thought of using a Goddess for the heroine". After thinking about what kind of heroine would be good, he ultimately decided on using a Goddess. He thought it'd be easier to get into the story if he used a famous God, so he ended up choosing Artemis because of that and because she was one of the "three virgin Goddesses" along with Hestia. He did some research and decided to have "Artemis" and "Orion" be the key words for the movie
"Was Artemis a character you were planning to eventually introduce in the novel?"
The author didn't really have any plans to do so but hoped he could if the timing was right. He reveals that he is planning on introducing Athena in the light novel. He believes that Artemis is better than Athena despite stories making it seem that the latter was better, and didn't really feel that she was a difficult Goddess
"So there was a motif about Artemis that drew you to her"
He doesn't want to comment that much because it'd be spoilers, but initially it was hard to grasp her character due to a certain setting, so he discussed her character a lot with the movie staff, nevertheless he feels she ended up being an attractive heroine. The author mentions that Artemis' design and the other characters' movie outfit designs were done by Kunieda (DanMachi manga artist)
"To prepare for this interview, I've looked at various stuff like the script and PVs, and I agree that Artemis is an attractive heroine. Do you think that attractiveness has grown by having Sakamoto Maaya voice her?"
The author agrees and states that he felt cleanliness seep out when he heard her voice Artemis, and adds that she did better than he imagined for the final scene
"How did you plan on showing the protagonist Bell's charm in the movie?"
The author states that the movie takes place between seasons 1 and 2, but admits that it's something that wouldn't fit in that time frame because the enemies are too strong and Bell's still immature. If the author added the movie to the main series, it'd require post volume 11 Bell for him to fight properly. "Therefore, people who know what happens beyond volume 6 might go "huh?", but I hope you'd ignore it because it's a different medium than the novel or TV (laughs)"
"Tell me some highlights about Hestia in the movie"
Oomori reveals that the staff called him coldhearted because in the first draft Artemis stood out but Hestia didn’t
"Did the producer say that?"
The author answers that it was the producer and staff. Sakurabi Katsushi was a part of season 1, but they never talked before movie, so he sugar coated it. However, staff members the author was friendly with (from season 1) told him that he (the author) cared about boys and not girls, and he admits it was hard having Artemis be cute and increasing Hestia's screentime at the same time
"How did you manage that?" (Artemis and Hestia's screentime)
Because Hestia is Artemis' friend, the author believed that she cared about the latter
"Tell me what other character I should look out for other than Bell, Hestia, and Artemis"
The author states that he wants viewers to pay attention to Hermes. He feels like Hermes is hated when reading fan letters, but he feels that he has an affinity for him
"I'd like to wrap up the first half of the pre movie interview, so please give fans who are excited for the movie a message"
The author mentions that the movie is both "DanMachi's come back" and "DanMachi is this kind of series". He didn't have that much confidence when he first started writing the script, but thanks to the power of the producer, staff, and cast, he feels that it'd be something Danmachi fans would enjoy in addition to showing new scenery. He asks fans to watch as if they were Gods excited for "the unknown"
Part 2[]
"In actual mythology, Artemis and Orion's story ends with the latter's death, but did that affect the movie's story?"
The author wondered how he could twist the original myth into a beautiful story and decided to switch their roles
"So Artemis' fate was decided at that moment"
The author admits that it's hard to add movie original characters into the main story, but denies that it's the reason why he killed her, stating that he wanted to write the best story he could using the movie only Artemis. The author planned on adding the concept of "separation" in Artemis' story and used that to have Bell and Hestia show emotions they normally wouldn't show. By having Bell finish things, he wanted to have her be "saved" rather than "killed"
"In the first half of the interview, you mentioned that Artemis' character was hard to grasp due to a certain setting. What did you mean by that?"
The author was referring to how the brave and virtuous Artemis became a girl that didn't know love, and how people who knew her from before like Hestia would be shocked. He mentions that it was difficult to portray her character properly in the beginning since viewers didn't know what she was like before
"You mentioned that Bell, Hestia, and Artemis' triangular relationship worked out well. I feel that was partly due to Hestia acting more adultlike in the movie"
"Like you said, Hestia's usual characterization ended in the first 15 minutes of the movie". Originally, the author planned on having Hestia realize Artemis' sad fate and urge Bell on, but changed it (based on producer and staff opinions and hints) to having the two Goddesses reminisce without Bell and have Hestia begin to realize the truth about Artemis from there
"You mentioned Hermes as a character you wanted fans to pay attention to, and I agree that he's a key character in the story. As a novel reader, I'm surprised that he didn't have any hidden intentions behind his words and actions (laughs)"
The author believes that Hermes showed his ego for the first time this movie after he saw what had happened to his old friend from heaven. He states that he wrote the story with a "Hermes guided Bell in order to stick to his ego of wanting to save Artemis" feeling
"At the climax, you had Hermes say "This isn't a story about killing a Goddess, this is a story about you saving a crying girl", and I felt that this represented the story and it really struck me"
The author mentions that as the author, he doesn't want to become a God that rules over his own story, but felt that Hermes voiced his (the author's) feelings
"Could you tell me how Bell riding the flying dragons clashed with the story?"
"The taming Ganesha and the others use isn't that omnipotent"
"While the Hestia and Hermes Familia left to go to the ruins outside of Orario, the Loki Familia stayed behind, and their battle is also shown. Was this an idea you had from the beginning?"
The rejected original plot involved the Hestia and Loki Familias fighting together, so the author took that and added it to the new plot. However, the author reveals that he originally didn't plan on including them in the new plot, as they only had 70 minutes in the beginning. Despite this, when he first submitted the script, he was told that what he wrote would only last for around 30 minutes
"That's short (laughs)"
The author reveals that they (the movie staff) told him he was being afraid and to trust them and do what he (the author) wanted to do. The original story just had Bell saving a girl, so he edited that to make it involve the fate of the world, and added the Loki Familia's fighting scenes in Orario. Upon reading the revised script, the movie staff suggested increasing the movie time to 80 minutes
"The movie had a lot of stuff, but could you tell me about stuff you weren't able to add?"
The author mentions his pamphlet interview, but answers the question anyway by mentioning that he originally wanted Ais and Lefiya to go with them. However the movie staff told him to have Ais stay behind because they wanted to see Hestia instead
"So Antares is a monster so strong that even the Loki Familia can't win"
The author mentions that being able to use arcanum as much as you wanted is basically a cheat. The only reason why they were able to fight against Antares properly was because it wasn't used to the arcanum yet and because it was using some of its power to operate "Artemis' Arrow" on the moon. If it didn't have any problems like those, something like a flick to the head would've easily killed Bell and the others
"I was going to ask "Who's stronger between Antares and the Black Goliath", but they seem like they're on different levels"
""Why was the Goliath and Antares black? Were there any other Black Monsters?" is all I'll say about this". Also, he jokingly worries that the publisher might get mad at him for saying that
"Lastly, could you tell readers what'll happen in the DanMachi series from here on within the area you're allowed to?"
The author reveals that DanMachi's finally at the halfway point (as of vol 14, but doesn't specify if there'll be 28 volumes total). The author worries that the publisher might get mad at him but wonders if he should spoil a little
"Please do!"
The author hints that something Hera related might appear in a different story after Bell's. He won't give any dates but mentions that it might end up as "I'm sorry, I foreshadowed her a lot but Hera won't appear this time" at the end of Bell's story (possibly a hint to a new DanMachi series after the main story ends?)
"So you're saying that the number of stories you want to write in the DanMachi universe is increasing?"
The author confirms it and brings up the movie, Memoria Freese, and Familia Chronicle. He refers back to the beginning of the interview where he stated that he didn't want the DanMachi series to end, and as long as circumstances allow, he'd like to keep on writing the world of DanMachi through the eyes of various characters