- "I think I've died and gone to heaven. These waitresses are all total babes!"
- —Masayuki Haitani
Masayuki Haitani (灰谷 真之 Haitani Masayuki) is the taller of Keitaro Urashima's two friends from the Sasagi seminar preparatory school.
A 2nd year ronin, Haitani is a playboy at heart likes to spend time with his buddy, Kimiaki Shirai, and chasing after cute girls.
In contrast to Shirai, Haitani is tall, lean and wears smaller glasses than either Shirai or Keitaro.
Relaxed and confident, he is always out to enjoy a good time and is quick to heckle Keitaro over his complicated relationships but he is also a steadfast and supporting friend when required to be; repeatedly bringing Keitaro back on track when his daydreams get the better of him.
While initially only possessing a 25% chance of getting into his first choice school, Haitani eventually manages to succeed; passing his exams while Keitaro fails and becomes a 3rd year ronin.
While Keitaro does his own thing, Shirai and Haitani eventually go to the beach where they enter the Beach Café Hinata and run into Keitaro again.
Staying with the Hinata group, Haitani attempts to help Keitaro pair up with Naru, but it backfires, causing her to hate Keitaro until Haitani apologises. In the café’s rendition of Journey to the West, both Shirai and Haitani play the part of Keitaro’s horse until they reveal themselves to be the demons Kinkaku (Haitani) and Ginkaku (Shirai). They are defeated by Monkey’s (Naru) self-replication technique.
The pair next run into Keitaro and Naru in Hinata on their way to work at Kanagawa Neverland. Haitani gives Keitaro a pair of admittance tickets to take Naru on a date at the theme park, however, due to circumstances Keitaro ends up having to take all of the Hinata girls; buying the remaining admittance tickets from Haitani at a discount.
During Christmas, Shirai and Haitani took up part-time jobs and, while assisting Keitaro in buying a present for Naru, met Mutsumi Otohime and accused and berated Keitaro about cheating on Naru.
It isn’t until the following year, during Halloween, that Shirai and Haitani visit the Hinata House to inform the residence of Keitaro’s situation; who was currently spending some time with his family in Tokyo.
As friends of the family, Shirai and Haitani are invited to Keitaro and Naru’s wedding, however Haitani can’t resist hitting on Motoko’s sister, Tsuruko, who declines his invitation somewhat forcefully due to being a married woman.
Attending Prep School, Haitani and Shirai catch Keitaro daydreaming about entering Tokyo University, whereupon Shirai announces that both he and Keitaro had failed the exam for the third time.
After meeting, and being pounded by, the top student in the school (Naru Narusegawa), Keitaro attempts to borrow some money from the pair in order to get to his grandmother’s hotel in Hinata.
After receiving some bad test scores, Shirai and Haitani attempt to pick up some girls; dragging Keitaro along with them. After a series of failed attempts the trio come across Motoko Aoyama, Sachiyo Matsumoto, Emi Ichikawa and Kikuko Onoue and, after Haitani attempts to make a pass to her, Motoko unleashes a ki attack on the trio after which Shirai and Haitani run away.
Sometime later, on the eve of spring and the arrival of Kentaro Sakata, Shirai and Haitani run into Keitaro with Kitsune on-board the Hinata tram and tempts him with discounted tickets to Kanagawa Neverland to take Kitsune on a date and forget about Naru.
Shirai and Haitani appear as hecklers in Motoko’s meditative dream over what she should do about Keitaro.
While investigating into the identity of the mysterious Indian girl who had attack Kentaro with an alligator, Keitaro asks Shirai and Haitani to ask around for information and while Haitani was unable to find any info on the mysterious currency she used, Shirai announces a theory that Kaolla was a “magical girl” from anime.
When the Hinata House residents go to the beach to help run the Hinata Sea-side Tea House, Haruka employs Shirai, Haitani and Kentaro Sakata to assist as well.
In the traditional rendition of the Journey to the West, Shirai and Haitani initially play the role of Keitaro’s horse until they reveal themselves to be the demon brothers; Kinkaku (Haitani) and Ginkaku (Shirai). However, as the play progresses and roles are switched, Shirai, Haitani and Kentaro attempt to steal the role of Son Goku from Keitaro.
In the pretext of helping Keitaro with his relationship with Naru, Shirai and Haitani arrange a visit to a haunted ship only to discover that the haunting was actually real and Haitani is attacked by a possessed Naru.
Following a summer festival the group returns to Hinata House where Shirai and Haitani manage to become mixed up in the arrival of Kaolla’s step-brother Lamba Lu and end up being used as robot weapons that Kaolla uses against her brother.
Come Christmas the pair, along with Keitaro, take up a part-time job selling Christmas cakes for some extra cash and come spring, following Keitaro’s belief that he had once again failed the Tokyo University entrance exam, Shirai and Haitani inadvertently show him an overseas expedition job which he takes and leaves without comment. The pair are later interrogated as to Keitaro’s whereabouts by the Hinata residents.
Negima! Magister Negi Magi
- Haitani has a guest appearance in Negima! Magister Negi Magi where Negi Springfield flips his car in the air to avoid hitting a cat on the road.
Ground Defense Force! Mao-chan
- A Haitani look-alike appears cowering with Shirai and Kentaro look-alikes on the security monitors during an alien invasion in Ground Defense Force! Mao-chan.
- Haitani has a magic trick; making a flower appear in his hand, which he is fond of performing to impress the girls.
- A running gag in the series is that the main cast keeps forgetting who Shirai and Haitani are when they appear.
- His surname means "ash valley" in Japanese, the ash being burnt residue, not the tree of that name.