Heartseeker Dragons are very social creatures that emanate a sweet chocolatey scent. Their captivating perfume easily attracts adult dragons that don’t yet have a mate. Heartseekers use their keen sense of smell to detect solitary dragons and potential mates in the area. By rubbing their fins against objects such as trees and rocks, they leave a scent trail for the other dragons to follow to meet each other. Although these dragons are seen year-round, the scent of a Heartseeker becomes particularly potent during the middle of winter. During this time, a single Heartseeker may play matchmaker to dozens of dragons, but he will also choose a special mate of his own.

Dragons are highly-intelligent reptilian creatures that—from a human perspective, at least—appear to live forever. Many different varieties of dragon exist, each with their own unique qualities, habitats, and behavior. Adolescence in dragons is usually marked by the growth of a hatchling’s wings, although not all breeds of dragons grow wings and some breeds have other traits that indicate the beginning of maturation. In Galsreim, dragons and humans coexist peacefully.

Dazai is usually called lazy as Kunikida always scolds him for being unproductive and slacking off. Despite that, he has shown a sharp wit, deducing all the unlikely situations that led Atsushi to believe he was being stalked by a beast when he actually was the beast in question. He has complete confidence no matter what type of situation he is dealing with, be it combat or simply bad situations he himself created in the first place. In most occasions, Dazai is overly dramatic, he takes most of his actions as a joke, and although they are very thought out plans he does not credit himself for most of what he has done.

His hobbies include being dramatic and annoying Kunikida. He also likes romancing females but never gets to finish it due to Kunikida interrupting his speech (often with some sort of physical action) about how she is ''the only one for him'' and ''the light to his world''

Despite having a warm personality, his fellow detectives don't know much about his past.