Tohka and Origami are able to distinguish the real Shido from the impostor, forcing Natsumi to retreat.
Natsumi sends Shido a letter with 12 photos of people close to him. She reveals she has replaced one of them and challenges him to identify the impostor before they all "disappear". Date A Live III (Dub) Episode 1
Natsumi uses her transformation powers to impersonate Shido at school, performing various "naughty" or offensive acts to turn his friends and teachers against him. Tohka and Origami are able to distinguish the