The story doesn't matter when they're on the screen.
There are many things that make a good anime. The story has to be engaging, the characters need to be believable and have clear motivations and diverse personalities. The animation matters a lot, of course, since everyone likes some visual pleasure.
But sometimes we don't really care about anything in an anime as much as we do care about a single character. And these are some of the best examples of that.
Yuno ― The Future Diary (Mirai Nikki)
Aired: 2011-2012
MyAnimeList score: 7.40
The Future Diary had plenty of fans back when it was airing, but now a lot of them don't even want to rewatch the series again. It was pretty great and exciting for teenagers, but now that they're older, they can't handle the edgy side of the story.
But Yuno will always remain one of the best anime characters ever. She's the only reason to come back to The Future Diary in 2024. Yuno's absolutely insane actions and personality make all the edgy moments worth it.
Kumoko ― So I'm a Spider, So What? (Kumo desu ga, Nani ka?)
Aired: 2021
MyAnimeList score: 7.45
No matter how questionable the story of the anime got sometimes, and no matter how bad the finale of the series was, Aoi Yuuki, who voiced Kumoko, carried the show single-handedly and proved that you can watch an anime just for one character. Even if it's a spider.
Yumiella ― Villainess Level 99 (Akuyaku Reijou Level 99)
Aired: 2024
MyAnimeList score: 7.14
Yumiella is not just the main villain of the series, she's truly the heart of it. Fans agree that there's no story without her, and the anime has to thank only this character for its 7+ score.
Yumiella's interactions with the other characters were the best part of the season, and she is the character that turned a generic isekai into something enjoyable.
Lelouch ― Code Geass
Aired: 2006-2007
MyAnimeList score: 8.70
Code Geass is a truly iconic anime, so Lelouch is not the only good thing about it, of course. However, he is the best thing about it, and there's no doubt about it.
Code Geass is a rather specific series with a lot of mindgames, intricate powers and mecha elements that so many fans dislike. But following Lelouch makes it all worth it.
Tanya ― Saga of Tanya the Evil (Youjo Senki)
Aired: 2017
MyAnimeList score: 7.96
Although fans mention that the novels the anime is based on have a lot of incredible characters, they admit that the adaptation failed to make anyone as interesting as Tanya.
Tanya drives the story, her personality attracts viewers so much that they don't even care about anyone else in the story anymore.