How many movies have Kana Ishida and Ken Ootsuka collaborated on?

They have worked on 4 movies together! Their first movie together was RahXephon: Pluralitas Concentio (2003) while their highest rated movie together was That Time I Got Reincarnated as a Slime the Movie: Scarlet Bond (2022). They have not worked together since That Time I Got Reincarnated as a Slime the Movie: Scarlet Bond (2022). They are most known for their animation films together.