RetHaida

RetHaida is the het ship between Haida and Retsuko from the Aggretsuko fandom.

Canon
Haida developed a huge crush on Retsuko sometime after they started working at the trading firm together, six months after they started working together when he caught Retsuko stealing water after work hours. Aforementioned by Fenneko, he had a crush on her for approximately five years to which he primarily kept it a secret (except from Fenneko). He explained that his reasons being, his first impressions and interpretation of Retsuko described her as vanilla until he saw her after work hours and decided to tail her and catch her in the act of putting her water bottle near the water machine. To his delight he found it fascinating and with that explanation - that's how the long term crush began, as well as him thinking she was cute. Since then, he tried working up the courage to confess to her. After Retsuko started dating Resasuke, Haida blamed no one but himself for waiting too long; he took their relationship very hard and went out drinking alone, catching pneumonia after dejectedly laying outside in the rain. Retsuko visited him in the hospital, informing him of her break up with Resasuke, leading Haida to finally confess his feelings. Retsuko politely rejected him, saying she knew how he felt and that she did like him, but that she simply wasn't ready for a relationship yet.

Haida later developed a complex after the rejection and couldn't talk to Retsuko, having nightmares regarding the rejection. After Fenneko told Haida that he should move on, Haida proclaimed he wasn't ready to and wanted to try again, but failed to ask her out to a Christmas party due to his nerves. After seeing Retsuko's lonely Instagram post while at a Christmas party, Haida ran back to the office thinking she might still be there working overtime, disappointed to not see her there. While walking back, he ran into Retsuko, Gori, and Washimi leaving a ramen bar. Gori and Washimi walked off, leaving Retsuko in the care of Haida, and the two decided to spend the rest of Christmas walking home together.

Months later, when news broke of Retsuko's relationship with Tadano, he became extremely jealous and sad, stating he was going to punch Tadano despite previously being a huge fan of his, showing that he wasn't letting it go, but his jealousy seems to have lessened after noticing that Tadano was upset upon leaving the karaoke bar, aware that Retsuko had privately ended her relationship with Tadano.

Haida, along with Fenneko, were aware of Retsuko hiding personal matters from him, and had since resigned to their current relationship as mere work colleagues despite his lingering sentiment for her. His feelings towards Retsuko became affirmed after she admits second-handed to having him as a friend instead of a work buddy soon after teaching her guitar lessons. He tries to spend some time with Inui to get his mind off Retsuko, but eventually he realizes that he cannot forget about her as Inui soon figures out he still has lingering feelings for Retsuko. He later saves Retsuko from an aggressive stalker, and finally realizes he really cares about her after Inui tells him to be honest with himself.

Fanon
In the fandom, this ship is extremely popular, and is the most written ship for both Haida, as well as Retsuko. This ship first became popular when Haida's feelings for Retsuko where revealed. However, many were disappointed that Retsuko did not reciprocate and was quite oblivious to Haida's feelings. Despite this it is still extremely popular, and became even more popular as they finally got together after Season 3. Fans fell in love with Haida's dedication to Retsuko.

Fandom
FAN FICTION "Haida/Retsuko tag AO3"WIKIS
 * Haida's relationship with Retsuko
 * Retsuko's relationship with Haida