ZoKu

ZoKu is the het ship between Roronoa Zoro and Kuina from the One Piece fandom.

Canon
Roronoa Zoro were childhood friends and rivals. The two started off on hostile terms due to their competitive nature with one another, however, they grew to have great respect for each other. They saw each other as rivals and contenders for the title, “World’s Greatest Swordsman” and promised each other that they would work to achieve this team.

They first met when a young Zoro wandered into a dojo owned by Kuina’s father. Zoro, who made a frequent habit of defeating a dojo’s best swordsman and taking their banner, requested to face the best swordsman they had to offer. Kuina stepped up and effortlessly defeated Zoro. As a result, Zoro chose to join the dojo and train until he could defeat Kuina. Despite his great improvements, and his determination in his training, Zoro still lost to China, frustrating him. Eventually, Zoro called her out in the middle of the night to face him once again, this time with real swords, and once more, he was defeated. Kuina then confined in Zoro the reality of a female swordsman and how Zoro would inevitably surpass her. Angered, Zoro made Kuina promise him that they would both work hard to become the best swordsman they could and reach the number one spot. The next day, however, Kuina died after falling down a set of stairs.

Despite their relationship not getting the chance to truly flesh itself out across the series, the pair shared a close bond that was forged in the heat of their rivalry. Zoro was frustrated that he could not beat Kuina, whilst Kuina herself would mock him. However, Kuina began to begrudgingly admire Zoro’s stubbornness and always accepted his challenge to her. By the time of their final spar, Kuina felt close enough to Zoro to confined in him about her insecurities of being a woman after her father bluntly told her she could not be the best swordsman in the world. She took great comfort in Zoro’s blunt retort and promised him that she would do everything she could to become the best and remain Zoro’s rival.

Zoro was evidently frustrated and angry with Kuina for being better than him, suffering an inferiority complex. However, he had great respect for her and viewed her as genuinely better than him and a true rival. When she revealed to him that she believes she will never be the best because of her sex, Zoro was furious and berated her for making excuses, especially after just defeating him, and made her promise him that they would become the best. Zoro was crushed by her death and was angry that she did not keep her promise. He initially held back his tears until he broke down in front of her father when he asked to have Kuina’s katana. He would occasionally believe she is watching him whilst training and screamed in anger when that wasn’t the case. Before leaving on his journey to become the World’s Greatest Swordsman, he visited her grave and promised to carry her dream along with his. Due to his unorthodox three sword style, he puts Kuina’s katana in his mouth.

No romantic suggestion has been suggested between the two, this is likely because of how young they were at the time. However, Zoro blushed when Kuina noted that her chest had started to grow whilst cupping one of her breasts. Also, three boys from the same dojo personally came to Zoro to tell him of Kuina’s passing, implying that the other students saw Zoro and Kuina as close friends.

Fanon
ZoKu is a positively received ship among the One Piece community but lacks any popularity due to Kuina being dead. Supporters of the ship believe that Kuina might still be alive due to her death being off-screen, however, the probability of this remains extremely low as her body was shown in the manga (albeit with her face covered).

Trivia

 * Kuina shares major connections to Tashigi, as both are swordsman, they have a direct relationship with Zoro, both their names come from flightless birds, they share an insecurity about being female swordsman and both have similar appearances.
 * Popular theories have emerged across the One Piece community that Tashigi, who shares major similarities with Kuina, is actually Kuina herself but there is no evidence for this. Furthermore, both Kuina and Tashigi were drawn differently as children.
 * Another theory is that Kuina and Tashigi are twins, or are related in some way, but no evidence has emerged proving this and its been stated that Kuina is an only child.