aura

A subjective sensation, such as a visual disturbance, preceding an epileptic seizure or migraine.

"She often experienced a flashing light aura before her migraine."

A supposed emanation or energy field believed to surround a living being.

"Some people claim to be able to see a person's aura."

A distinctive, pervasive atmosphere or quality surrounding a person, place, or thing.

"The ancient castle had an aura of mystery."