Yu-Gi-Oh! has a diverse list of characters that both support and oppose Yugi and the pharaoh. Of these opponents, perhaps none feature as prominently as Yami Bakura: the haunted youth who survived the tragedy of Kul Elna, the village sacrificed to create the Millennium Items. Though the Yu-Gi-Oh! franchise has taken a light-hearted approach in recent years that grounds itself more and more in science fiction and shonen, if it ever wanted to explore its own dark side, a series about Bakura in the more adult seinen genre could serve as its golden ticket.
Yami Bakura, known as Thief King Bakura during his lifetime, serves as a brilliant foil to the Pharaoh. He's teased to be powerful from early on in the series, being able to defeat the formidable Maximillion Pegasus in a battle between their Millennium Items in the conclusion of Duelist Kingdom. Though Yami Yugi defeats him in the Battle City quarterfinals, the villain attempts to get revenge during the Dawn of the Duel arc. But for all that, he's also simplistic in his motivations. His hatred towards the kingdom originates in the massacre of the village he grew up in, Kul Elna. But 5,000 years later, that hatred manifests as... tormenting innocents who just want to play card games. Certainly, their ownership of the Millennium Items plays a part, but for someone that holds the title of "Thief King," you'd imagine he'd have better ways to take the artifacts out of their hands.
For Bakura, there's much that can still be expanded upon because we never get to actually understand him. For viewers of the anime, Bakura's primary character trait is revenge. It's his need for revenge for the massacre that created the Millennium Items, and eventually, that need for revenge fuels his obsession to obtain the power of the artifacts. Otherwise, he only shows up to confront the Pharaoh and his allies. But we never get to see him reflect or understand any other motivations he has, and we're left wondering what he wants to do if he emerges victorious. Presumably he'd set himself up as king, so how would his tragic past and commoner upbringing affect his rule? What are the principles he believes in, if any at all? We don't know, and so, despite being a brilliant foil to the pharaoh, Yami Bakura is rather undeveloped.
It's not just Bakura's character that could use some development, either. His village of Kul Elna is described by Aknadin as a village of thieves responsible for much chaos, while in the English dub it's said that they're possessed by dark spirits and have been robbing the graves of royalty for years. While we never know if this is actually true or not, it's certain that Egypt is facing internal battles in addition to external ones. If it's true that Kul Elna was a village of thieves, then it speaks to the economic state of Egypt that an entire village has to turn to grave robbing. If it's not true, then it speaks to how easy it is for the government to create a scapegoat.
With greater insight into Kul Elna, Bakura's story can be transformed entirely. In the anime, the Thief King's journey is portrayed as an evil man obsessed with revenge. But with a little more backstory and a greater focus on Bakura as the protagonist, it can be seen as the last survivor of Kul Elna attempting to overthrow a corrupt system so that no one suffers the fate of his village. But that journey doesn't have to end in victory. As he sees the corrupt hailed as heroes and outcasts like him declared criminals, he falls into hopelessness. The very villagers he wants to save now root for his enemies, and he develops a defeatist attitude as his chances of victory grow slimmer and slimmer due to Yugi and his friends. And finally, believing the whole world to be corrupt, he sacrifices himself to destroy it entirely by summoning Zorc Necrophades.
Of course, that's just one way of many to approach it, but the seinen possibilities that Bakura presents are endless. If Yu-Gi-Oh! ever wants to venture into the genre, then one of its most popular and enduring characters should be the one to lead that charge. Though he lacked development in the original anime, expanding on Bakura's character offers much insight into the story of one of Yu-Gi-Oh!'s most legendary villains.