There are times when the ending to a manga doesn't satisfy fans and they choose to ignore it. Usually, this is because a romantic pairing didn't come to fruition or because characters make choices that are questionable at best. For fans of Usagi Drop, the problem isn't that they didn't get a romantic pairing -- it's that the pairing they did get was between a man and his adopted daughter.
30-year-old Daikichi Kawachi goes to his grandfather's funeral to discover that Souichi fathered an illegitimate child named Rin, just six years old at the time. The family despises her because of this, so Daikichi takes it upon himself to adopt her. He befriends another single parent named Yukari Nitani, who helps him try to raise Rin by himself.
While the anime's story only spans about a year, the manga follows Daikichi and Rin's relationship as parent and child up until Rin reaches high school. It's here that Rin begins questioning her feelings about Daikichi, and her friend Kouki, the son of Yukari, tries to help her confess her feelings to Daikichi even though he has feelings for her himself. The series ends with Rin confessing her feelings and Daikichi telling her to wait until after she graduates high school. At the very end, Rin declares that she wants to have a child with him.
This ending was controversial, to say the least. Many fans were outraged that Daikichi, who raised Rin as a daughter, would even entertain the idea of being with her romantically. Some readers didn't really hate the ending, while others downright despised it and claimed it ruined the entire series for them. The first half of the story built up the father-daughter relationship, even though Rin declared numerous times throughout the story that she never saw Daikichi as her father. This isn't unusual for step-children, even in the real world. After the time-skip is when many fans say things went downhill fast.
The anime did not go along with this ending, instead concluding when Rin is still young and with Daikichi reflecting on how far they've come as a family. There is no time-skip and no confessing of feelings. Many fans consider the anime superior in this aspect, not wanting it to end on such a controversial note. Because of this, some fans even denounce the manga as a whole and consider the anime the true story. Even though it isn't technically incest, the thought of a man marrying the child he raised made plenty of fans highly uncomfortable.
Even after Rin confesses her feelings, Daikichi says that he loves her like his own child. Fans of the ending have therefore argued that it isn't so weird because Daikichi wasn't setting out to groom Rin -- she was the one to pursue the relationship. However, denouncers say that regardless, Daikichi should have shut it down, being the adult in the situation.
Does the manga ending ruin what the anime set out to do? The answer depends on the person, but an argument could be made that yes, knowing how their story ends could ruin the anime. If someone were to start with the anime and then move on to the manga, their previous experience could certainly be dampened. Some say that there were hints of a romantic relationship early on, but others argue that the focus should have stayed on the wholesomeness of the father-daughter aspect.
It's a divisive topic among anime fans, with forum posts devoted to talking about the ending and if it ruins the series. Whether or not that's true is up to the viewer, but it's definitely been one of the most controversial manga endings either way.
