The Romance Between the Condor and the Swan- Gai Yuki and Kaori Rokumeikan
I don't know how many people felt like they should have ended together but I wasn't one of them, sorry but let's get this moving on. Now let's move on with the story on how this relationship came and went in Jetman. So the details? Kaori was a bored rich sole heiress to her family, engaged to a jerk named Shouichirou while Gai Yuki was a flirt, a bum (looks like it!) and both one day got selected by fate to become members of the Chojin Sentai Jetman. The story gets far deeper than the fan pairing of Joe x Jun in Gatchaman.
At first, it seemed nobody would think that Gai Yuki would get attracted to Kaori for the earlier episodes, when he realized he was really needed into the Jetman team, he seemed to show an interest on both girls Ako and Kaori. But he did show signs of being concerned for Kaori like when he tried to shield her from Ryu's temper or two, when he did all he could to protect her. He told Kaori that she would certainly fall for him but she fell for Ryu after ending her arranged marriage with Shouichirou (who Gai kicked). And during the time Kaori couldn't walk out of a psychological shock, Gai Yuki attempted to flirt with her when they were alone but she slapped him... it became love at first slap.
Of course, Gai Yuki wasn't going to let Ryu beat him while the latter was loving a shadow, not exactly a shadow since Rie was turned into Maria. However on Ryu's birthday, Kaori's feelings for Ryu were shown to be growing one by one like never expected. Frustration after frustration came for Gai Yuki to why Kaori would not answer those feelings even if he risked himself to save her from Maria's album created by Camera Jigen. Kaori found Gai Yuki to be "too wild" for her tastes while suffering from what looks like unrequited love from Ryu, and to Gai Yuki, from Kaori. And of course, it was a violent polygon since Gai Yuki challenged both Ryu and Raita to a fight for Kaori. Gai Yuki showed signs of being a nice guy but, Kaori was too wowing over Ryu.
But eventually they did surface. When Kaori got kidnapped by Mu who intended her blood to be used to revive the other two demons Ramu and Gogu, Gai Yuki decided to offer his own blood to save her. Kaori pleaded him to stop but he refused to, the Jetmen were able to save him before he died in that incident. She fell for him eventually, Gai Yuki won the bet but the relationship wasn't meant to last. So they did put feelings over duty first but when Ryu got dazed into a delusion that he was still with Rie, it was also them to return the favor by attempting to snap the latter out of it.
So Kaori was thinking of her marriage with Gai but trying to introduce him as a businessman instead of the man he was, the latter realized that they weren't compatible especially in meeting the girl's parents. Ako suggested to Kaori she was better off with Ryu. Though try to patch up the relationship they did, the two still remained friends nonetheless. In fact, Gai Yuki trusted Kaori with helping Ryu overcome his vampirism which was caused by the same starfish parasite that latched itself unto Maria. In the end of the series during the wedding day of Ryu and Kaori, Gai Yuki dying from a distance without noticing gave his blessings too. The end.