The character of Diva in DSOD was a mistake

I admit I haven't watched every piece of Yu-Gi-Oh media, but of the ones I have seen, Diva might be the single worst main antagonist. I rank him up with Anubis, Siegfried, and Kagemaru as one of the worst villains in the franchise.

Given the plot of DSOD is about Kaiba's inability to move on from Atem's death, I used to question why the movie even needed a villain in the first place. Obviously the truth is that the movie didn't need a villain at all, Diva has no relevance to its main story.

Then I realized what he does contribute. Diva's purpose is to create a situation where Atem has to swoop in and come to the rescue, even though the message of the movie is moving on from Atem passing to the afterlife. Diva's purpose is to undercut the message of the movie. That isn't intentional but aside from fanservice by referencing earlier plots points, that is all he adds.

I might be more willing to overlook this all if Diva weren't an unlikable jerk who does everything in his power to kill any sympathy I may have had for him. He has a sad past where he grew up poor and so his surrogate parent was killed right in front of him. That might have made him a sympathetic character if Diva hadn't become a mass murderer who uses his magical powers to go around the globe killing people he deems evil. Given he felt Joey standing between Diva and killing Bakura was, in Diva's eyes, a crime punishable by death, this gives the feeling Diva murdered lots of innocent people for petty reasons. He's basically a nicer Light Yagami.

If trying to kill Joey wasn't bad enough, Diva also tried to murder Yugi and the rest of his friends because he was afraid Yugi would cause Atem to return, even though they all considered him a friend. All because Diva didn't want to lose the magical powers that he had been using to kill people. What a nice person deserving of our sympathy. Yeah Diva screwed with their memories so they thought he was their longtime friend, that makes Diva willing to kill them all so readily even worse. He rewrote their memories, then tried to murder them all with no hesitation.

While Diva loses his powers, since he takes his loss so gracefully there isn't anything narratively satisfying about it, especially since he just seems to walk away despite all the murders he committed and his attempt to kill our heroes.

Undercutting the message of the movie, being an unlikable character the audience is expect to sympathize with, Diva is frankly worse than the garden variety shonen movie villain who is just an excuse for action scenes on a higher budget.