Season 1Jibanyan tells Nate he has to shove his arm into Whisper's mouth in order to switch watches, something Whisper called uncool.
In episode 130, Whisper sacrificed all his body parts in attempts to get the Yo-kai Watch Dream, but he kept failing. However, he did manage to get the Yo-kai Watch Dream by trading with Walkappa.
Whisper pledges loyalty to Nate by becoming his butler after being freed from the Crank-a-kai by him. Though he tries to be useful to Nate, he in fact, annoys Nate by dismissing his suspicions about Yo-kai, claiming he hadn't heard of a Yo-kai behind a supernatural event only to usually be proven wrong. Although Nate can be easily annoyed by Whisper's lack of useful knowledge about Yo-kai, he still holds a strong bond with him, as seen after being cut by Shogunyan, he cried his "death", only to reassure himself and share a warm moment. Their bond is stronger in the English dub than in the original Japanese. He uses the Yo-kai Pad very often because of his past history as Nonuttin (aka Whispocrates).
Jibanyan was a cat that got ran over by a truck, then turning into a Yo-kai. Whisper and Jibanyan are both found around Nate very often so they end up interacting with each other a lot. Jibanyan is also the only one (besides Kin and Gin) who knows about Whisper's past form. In the dub, Jibanyan's characterized to like to beat up on Whisper more, when Nate first get the Yo-kai Watch Model Zero, Jibanyan says "If you want to switch watches, you have to punch Whisper in the face. I approve." In spite of this, Whisper and Jibanyan are friends.
They can also fuse together to become Buchinyan.
Komasan had the unique personality of trying to eat Whisper's Ice cream- like head. Komajiro didn't meet him or Nate, so his brother possibly told Komajiro about him under the name of " Whiscream".
USApyon and Whisper don't get off to a good start as Whisper misreads his name as 'U-S-A-pyon'. The two are willing to work together beyond that short misunderstanding.
Whisper seems to have a rivalry with Verygoodsir. With both of them being butlers, Whisper often tries to outdo him.
Whisper has a huge amount of admiration and respect for all Classic Yo-Kai, to the point where it can pass off as an obsession.