Kyoshi began her immortality technique for the day. She punched downward into the Earth. The immortality technique actually was not difficult. It was an inversion of the earthquake technique.
Using earthbending to cause earthquakes was the highest taboo in earthbending cultures. In every nation, save the air nomads, it was punishable by death. The earthquake technique involved using one's body to reverberate vibrations throughout the Earth, usually to find a fault line that was overdue and then cause trouble from there.
The immortality technique was the opposite. Feel the natural vibrations of Earth and allow them to move through one's body. Kyoshi felt the crust, the mantle, the outer core, the inner core. She could feel people dancing on the other side of the world. Now she allowed the vibrations to enter her body. First she concentrated on her body as a whole, then her organs, then the tissues of those organs, and then finally to the cellular level.
In her mind's eye she could see a sun dial. First the shadows of the dial moved one way, as they would with the passing of the days, then they moved backwards. She pictured seasons moving backwards, leaves became flowers became buds and then disappeared. Snow appeared on the ground as did dead leaves. The snow disappeared and the leaves ascended to the barren trees then turned from browns and oranges to green. This was when Kyoshi knew she was done. She lifted her fists from the Earth.
Of course, "immortality technique" is a bit of a misnomer. Every time Kyoshi used it, she got less time back for the amount of time she spent doing it. At first she merely had to do it for five minutes a day for rejuvenation, now an hour. That is, whenever she could find the time to do it. That said, she kept her youthful appearance and appetites long after all the other avatars were dead. Kyoshi already had a fearsome reputation, but having seemingly conquered death itself made her the most feared avatar in history.
Kyoshi was merciless in combat, but was foremost a pragmatist who preferred diplomacy over brutality. Her network of spies told her that the noble families of the Water Tribes, the Earth Kingdom, and the Fire Nation believed that they existed at Kyoshi's pleasure, which was half true.
Her mind was also sharp. The memories of her former lover Rangi, both their time together, along with Rangi's passing were as fresh as they were when Rangi died. Every year on the anniversary of Rangi's death, Kyoshi tortured herself by watching a play of their relationship. On occasions like this, she would cross-dress as a man in order to not arouse suspicion.
They could never get the casting quite right. The actress who played Kyoshi was taller than most actresses, but not tall enough, more plain than most actresses but still too beautiful be Kyoshi. It was easier to find a Rangi actress, the face and the height were alright, but none of them ever had Rangi's muscular build.
Like everything else the theatre did, they intentionally got details wrong in order to dramatize what actually happened. Kyoshi and Rangi were on the left end of the stage while their enemy, one of the lesser lords of the Fire Nation who was opposed to Kyoshi's "suggested" land reforms was on the other. "I'll be damned if I am to allow my family's lands to be taken by a couple of perverted degenerates such as yourselves!" This particular lord was actually one of Kyoshi and Rangi's strongest boosters when it came to their relationship, but also the greediest when it came to his own land.
"Hya!" the lord stabbed at Rangi's midsection. The actress had fake blood coming out of her mouth while actress-Kyoshi held onto her. "No, please, stay with me, don't go. HEALER!" Actress-Kyoshi screamed for a water tribe healer that did not come. Actress-Kyoshi was crying, but the tears did not smear her makeup. A distracting detail. Actress-Rangi held her hand against actress-Kyoshi's face. "Kyoshi... the time that I spent with you was the best of my life. You made it worthwhile. Leave me behind. Balance the world. Move on from me."
Actress-Rangi died. Actress-Kyoshi let out a primal scream. The lights turned down low and Actress-Kyoshi's glow-in-the-dark makeup activated, giving the illusion of the avatar state. The play ended as it always did, with Kyoshi killing the lord's guardsmen and the lord himself, avenging her lover's death.
Kyoshi watched this play because that's how she wished it had gone down. By the time Kyoshi had found Rangi, the battle was over and she was already dead. An arrow hit her neck, severing one of her arteries. Kyoshi remained stoic, calmly asking her assistants to take Rangi's body and prepare it for a proper funeral. The next day the lord surrendered and offered his sincerest condolences for the loss of Rangi. Kyoshi delivered the news to Hei-Ran herself. When Hei-Ran saw Kyoshi sans Rangi she immediately knew what happened and fell to her knees, sobbing.
The play was over. Kyoshi was about to make her getaway when she quite literally bumped into one of the cast. The actress that played Rangi. "Oh, you're the avatar!" This made Kyoshi furious. Was she getting careless in her old age? Perhaps dementia was setting in despite the immortality technique? "I knew you were the avatar because I saw you last year!" Kyoshi looked down at the actress. The actress was biting her lip. She was wearing an outfit that accentuated her shapeliness.
Kyoshi sighed. She had seen this many times. Groupies. The desperation turned her off, but then again, it had been awhile. They went and got dinner and drinks, had a long, admittedly pleasant conversation, then the actress invited Kyoshi to her place for "tea." This, like many other times in Kyoshi's life, was entirely transactional. Kyoshi got some momentary pleasure and a night of not thinking about Rangi, while the other party got the thrill and bragging rights of having fucked the avatar.
"So, before we begin, could you put on the Kyoshi-makeup? I have a kit you can use!" Kyoshi obediently did so. Kyoshi preferred to wear makeup during these one night stands anyway. In the midst of their love-making, the actress asked Kyoshi if she could transform into the avatar-state, which again, Kyoshi did. Having done so many times, the avatar state had no novelty for Kyoshi, but for a random partner it made their night. The actress gleefully clapped in the nude at Kyoshi's display before they continued.
The next morning, Kyoshi made the walk of shame back to her quarters. "Again?" her guard asked. "Again." Kyoshi answered. Kyoshi began the ceremony that was supposed to conclude Rangi's death-anniversary. Out of a box she took out Rangi's sweat cloth. It was the last thing Rangi gave to Kyoshi before her last battle. In the decades since Rangi's death, it had lost most of its scent, but a small portion still lingered. Who knew how long that would last. Kyoshi sniffed it while sobbing, the tears smearing her makeup. She did not only do this on the anniversary of Rangi's death, however. This was Kyoshi's nighttime ritual every night.