Insomni is a yo-kai who are similar to ghost. Yo-kai can only be seen with the help of the yo-kai watch. Insomni when she inspirits you you will get insomnia and won't be able to sleep. She claims that it's fun and sleeping is boring. She has a rivalry with Baku another yo-kai because Baku will make people sleepy so basically her opposite. She will only stop inspiriting you when she gets bored. If you befriend insomni she will give you her yo-kai medal so you can summon her at any time.