Kaiki Deishū

A con artist specializing in fake apparitions. He first appears in "Karen Bee." Main character in "Karen Bee" and "Hitagi End."

A middle-aged man who speaks in a monotone voice, dressed in a pitch-black suit and tie. He is consistently described as "ominous" by everyone he meets. Although not as knowledgeable as Meme in apparitions, he possesses high expertise but does not believe in their existence. He has used what he calls fake apparitions twice. His policy is to only tell half the truth. His catchphrase, used as a reflection for himself or his conversation partner, is "The lesson that XX (the person who should learn) should learn from this matter is." When he has a substantial amount of money, he tends to spend it lavishly but does not carry bulky items.

Due to the nature of his job, he does not have a permanent residence and has sold his family register. Like Meme, he leads a nomadic life, but unlike Meme, who prefers ruins, he prefers staying in city hotels.

When working (scamming), he goes out of his way to buy an A4 size notebook, meticulously planning by writing detailed notes and maps with caricature illustrations. He uses jargon to ensure that even if someone peeks, they cannot understand, and he takes pleasure in reviewing the progress of the scam. His passion leads to several notebooks, but he discards them all once the job is done.

He is the mastermind behind making "charms" popular among middle school students like Nadeko. When Karen called him evil, he neither denied nor took pride in it, accepting it as a matter of course. Unlike typical villains who proclaim their justice or goals, he is just a "mere villain" who found scamming to be an easy way to make money. He is pragmatic, readily yielding to younger ones like Hitagi when necessary, but he is also very competitive and thrives in adversity.

He was one of the first to scam the Senjougahara family, prompting the parents' divorce, making him a deeply resented figure for Hitagi.

Meme, Yotsugi, and he were university classmates and belonged to the same club (Occult Research Club). He seemed to have difficulty with Meme and Izuko due to personality clashes. However, at the beginning of "Hitagi End," he refers to Meme as his best friend (which might be a lie [citation needed]). He was also in the track and field club in middle and high school, capable of catching up with the sprinting Suruga with ease, a running style he calls "Kaiki Stride." However, he also claims to have specialized in shot put.

In "Hitagi End," at Hitagi's request, he ignored Izuko's advice and confronted Nadeko alone to save Koyomi, Hitagi, and Shinobu from her.

Later, there is a depiction of him being attacked by a middle school student cursed by a "charm" counter-curse, but the truth is unclear as "Hitagi End" is narrated with lies interwoven. In the anime version of "Koyomi Dead," a person resembling Deishu, with his head wrapped in bandages, appears.

He has known Tooe and Izuko for a long time, and in "Suruga Devil," he talks about having had feelings of admiration for Tooe during their university days, and he views Suruga favorably.