suspicious, mystery, apparition
恠 centers on a feeling of unease about something not understood: suspicion, mystery, or a ghostly apparition. The meanings share the idea of something strange that unsettles the mind.
恠 is a variant form of 怪. Both combine the heart radical 忄 with a phonetic component, but the exact historical development of the 在 component in this variant is uncertain.
The heart radical 忄 shows this is about feelings. The right side 在 suggests something present or existing. Imagine a strange presence that makes your heart feel suspicious—a mystery or ghostly apparition.
For カイ, imagine a mysterious figure whispering 'kai...' in the dark, making your heart pound with suspicion. The eerie 'kai' sound cues カイ while the apparition lurks nearby.