Ranma and Akane are engaged to each other because of a long-standing agreement between their fathers. Soun Tendo is particularly invested as he has no male heir and needs one of his daughters to marry a martial artist willing to carry on the Tendo Anything Goes Martial Arts Dojo. Despite the couple regularly bringing up their lack of agency in the initial decision, neither have broken off the engagement permanently. Perhaps more telling is their constant fits of jealousy when the other gains a new suitor or is placed, however unwillingly, in compromising situations with said suitors.
When Ranma and Akane first met, Ranma was in girl form, and Akane, believing her father made a mistake when he said Ranma was a man, tried to befriend her. But later that night, when she went to take a hot bath, she ended up seeing Ranma in boy form, and was horrified, running around the dojo screaming and grabbing the dining room table to pound him with. Once the curse was explained to the Tendos, Akane was dragged into the arrangement by her sisters, since she claimed to depise men, and they believed Ranma's curse would help the two get closer. Initially, the two were not pleased with the engagement, having just seen each other naked due to the confusion over Ranma's gender. Akane's angrily fearful claims that he was a pervert only served to irritate Ranma, who retaliated by taunting her over her walking in on him and his female form being "better built, to boot." However, with urging from the Tendos, Genma Saotome, and Tofu Ono, they slowly came to treat each other with more respect. Their relationship is still characterized with caustic insults and flippant remarks about their lack of consent in the engagement, but they often look out for each other and will go out of their way to do something nice for the other.
Akane fits the role of a tsundere, a character who is rude and defiant of her love interest but inwardly desires to be close to him. She is cheered by considerate words and actions, though often they turn out to be Ranma acting in his own self-interest. When Ranma is courted by any other woman, she becomes flustered and usually takes her frustration out on him. There are many times that she has gone out of her way to do something nice for him, and is stubbornly motivated to improve her abysmal cooking skills to prove to him that her cooking is best. Her pride and shyness often keeps her from saying more than "Ranma, no baka!" (usually translated as "Ranma, you jerk!"). Her strongest moments come when Ranma is missing from the Tendo household due to training and kidnapping. She has hiked far into the wilderness to find him and has put herself at risk to help him train. It seems that Akane may claim that Ranma means nothing to her, but cannot be at peace knowing that he is not around. Of note is her respect for his agency in romantic relationships. She will not stop him from pursuing other interests but will not manipulate him into loving her, unlike Shampoo or Kodachi Kuno.
Ranma, as the principal character in a harem anime, has no shortage of women seeking his hand in marriage. Though he may play it down or protest that it wasn't his decision, he never outright denies his engagement (though he has gone on dates with others when blackmailed or when it is in his interests to do so). In addition, when Akane is being courted by others, he is quick to blow his top and threaten men who try to woo her. His unkind actions tend to stem from his large ego and a comedic naivete about the feelings of others. While he often offends Akane due to a mixture of these traits and some bad timing, he will usually come back and try to rectify the situation. In particular, his ego instills a competitive desire to be able to best her in a number of situations. Perhaps he has a fear of appearing weak in front of her. He has certainly gone to great lengths to protect Akane and has been shown worrying about her when she is handling challenges on her own. It seems that Ranma may act like he is fine on his own, but remains fiercely loyal to Akane even when other alternatives seems more attractive.
Moments in the Anime
Ranma generally does not want to admit any affection for Akane but it is shown in the episodes "P-Chan Explodes! The Icy Fountain of Love!", "Close Call! The Dance of Death... On Ice!", "The Abduction of P-Chan", "Kuno Becomes a Marianne!", and "Ranma the Lady-Killer" that he loves Akane. He does at times show that he cares in some way. In these instances, he typically brushes the gesture off (i.e. saying that he didn't mean it, or didn't have a choice). This is met with two responses: If he shrugs the gesture off as unimportant, Akane tends to become angry, frequently striking him. When Ranma does something important and downplays it, Akane appears hurt.
In the episode "Akane Goes to the Hospital!" Ranma shows how much he cares about Akane. In the beginning of the episode when Hikaru Gosunkugi takes pictures of Akane, and when his classmates asked to take pictures for them also, Ranma tries to stop them, and seems quite agitated when they continue. However this backfires as Akane gets hurt when Ranma's classmates are trying to restrain him. Akane falls and sprains her ankle. In the clinic all of her classmates and family members visit her except Ranma, who in the meantime is outside the clinic window pondering what to say to Akane to make her (and himself) feel better. He then daydreams about Akane and in both the dreams he has, he finds himself wanting to kiss her. The next day (having been unable to visit Akane the day before due to Tofu Ono almost catching him outside her window) he leaves a bouquet of flowers outside her door, still being unable to muster the courage to face her.
At the end of the episode, when he hears she is coming home from the hospital he stays up all night to make her a banner emblazoned with the words "I messed up, I'm sorry." and waits for her as she hobbles out of the clinic. However, as his luck would have it, the entire gang finds them and they break into a mad chase, with Ranma having swooped Akane onto his back. They run off together until Akane manages to make them both trip.
In the episode The Frogman's Curse!, Akane sacrifices herself for Ranma in a fake attempt to turn herself into a frog. Ranma is shown to have teared up in this scene.
If you watch the OVA 8 (the second part of the OVA 7), Ranma got jealous over her and Shinnosuke. Also in the last few minutes of the second part of OVA 8, Ranma blushes and reaches out for Akane's hand and they walk home holding each other's hand.
The ending theme from OVA 1 to OVA 6 have them singing a ballad together.
Moments in the Manga
After the battle from Mount Phoenix, Ranma and Akane were going to marry each other. Unfortunately, their wedding got interrupted by Shampoo, Ukyo, Kodachi, Kuno and etc.
- P-Chan Explodes! The Icy Fountain of Love!
- Kissing is Such Sweet Sorrow! The Taking of Akane's Lips
- The Frogman's Curse!
- Nabiki, Ranma's New Fiancée!
- A Xmas Without Ranma
- Akane Goes to the Hospital!
- Let's Go to the Mushroom Temple
- Reawakening Memories Part One
- Reawakening Memories Part Two