Jealousy often pushes people to unorthodox, possessive actions, so anime characters with jealousy issues can drive a storyline.
In some cases, a character's thirst for superiority prompts them to work hard and improve themselves. Mello from Death Note probably wouldn't have developed his logical thinking skills if he weren't constantly pitting himself against Near. While his ceaseless envy does lead him to join gangs and kidnap civilians, the expectations placed upon him at a young age make him seem like a sympathetic villain.
Unfortunately, Mello is a rare case, as plenty of jealous anime characters push the limits of acceptable behavior. In Shuffle! Kaede Fuyou becomes wildly jealous of any girl her beloved Rin talks to, leading her to violent behavior.
Whatever form it takes, jealousy is a human emotion, and although its presence can make a character unlikable, that doesn't mean they're not relatable.
If Yuno Gasai had a middle name, it would be "jealousy." She can't stand the idea of anyone getting near her precious Yukiteru Amano. If she suspects someone is endangering her romantic bliss, she will not hesitate to kill them.
This doesn't mean Yukiteru is safe from her violent behavior —that jealousy can, and often does, turn on him. To be fair, Yuno eventually learns from her mistakes, but that's only because she luckily has the power to right her unspeakable wrongs.
Inuyasha and Kagome are equally jealous, which may be part of what draws them to each other. Inuyasha competes for Kagome's affection with anyone he thinks might be interested and gets heated even when it's obvious Kagome doesn't reciprocate the other person's advances.
Meanwhile, Kagome finds it nearly impossible to tolerate Inuyasha's continued affection for Kikyo. While the mutual jealousy isn't exactly healthy, it does help the couple understand each other, since they're both coming from the same place.
Katsuki Bakugo Thinks Izuku Midoriya Looks Down On Him In 'My Hero Academia'
The rivalry between Katsuki Bakugo and Izuku Midoriya is a strange one. Izuku just wants to be friends, but Katsuki's wild jealousy blinds him to Izuku's genuine attempts at camaraderie.
Instead, Katsuki insists Izuku thinks little of him, which couldn't be further from the truth. Nonetheless, this makes Katsuki furious, and causes him to isolate himself not only from Izuku, but from everyone else. If he has to be better than everyone else, he can't exactly be friends with them.
You might not think that the all-powerful prince of Saiyans would have anything to feel jealous about, but Vegeta can't stop comparing himself to his rival, Goku. He wants desperately to prove himself superior, but eventually he does learn to appreciate his own abilities and stop comparing them to Goku's.
However, he remains jealous when it comes to his wife Bulma. When Goku promises Old Kai he'll show him some sexy pictures of Bulma, Vegeta's furious, which honestly isn't the worst thing. Those aren't Goku's, Old Kai's, or Vegeta's pics to show, after all.