YamaLu

Luffato is the Slash ship between Monkey D. Luffy and Yamato from the One Piece fandom.

Canon
When they first met, Yamoto saved Luffy from Ulti, Yamato immediately knocked Ulti out in one blow, and quickly carried Luffy off to a private space to talk and reveal being the son of Kaido. However, Luffy was in a hurry, and tried to escape and they clash, which Yamato felt was familiar. Eventually, Yamato took Luffy to the attic immediately after their clash and was able to get him to stay and talk for five minutes, in which Yamato first discussed how Oden had left behind a log and that someone needed to carry on Oden's will. Upon Yamato revealing he was actually a girl, Yamato explained that since Oden was a man, then it was also necessary to become a man as well.

Yamoto gets along with Luffy, and has great respect for his strength and courage. Luffy, likewise, sees Yamoto as a great ally and friend. Yamato declared that he would sail across the sea with Luffy upon facing his father, Kaido.

Luffy refers to Yamato by the nickname "Yama-o", though he doesn't understand and often corrects Luffy when he calls him that.

Fanon
The ship has gained a noticeable following after the introduction of Yamato. Fans of the ship appreciate the subtle treatment of Yamato identifying as a male, despite being born a woman. As of the moment, Luffato is unpopular compared to most Luffy ships.