On the other hand were people who hated the ending with every fibre of their being, claiming the twist turned what was a heart-warming story of a father and daughter into the plot of a bad hentai out of nowhere, with no foreshadowing or implication that Rin and Daikichi’s relationship was anything other than strictly parental.
https://www.reddit.com/r/HobbyDrama/comments/kw3tvj/manga_the_infamous_ending_of_usagi_drop/

