Johan Liebert

Johan is the greatest antagonist in fiction-

Johan Liebert-

There's no doubt

...

Forced to live as a traitor and join the Akatsuki, Itachi carried the burden of this tragedy, acting as a secret protector of the Leaf Village while appearing as a villain to motivate Sasuke to become stronger.

We could consider someone like Johan as well.

Born from a eugenics experiment and traumatized by severe childhood abuse, including time in the abusive Kinderheim 511 orphanage, he developed a nihilistic worldview seeking to be the last one alive at the world's end.

Then there's Pain, whose backstory is rooted in the pain of war, losing his parents to Konoha ninja and witnessing his best friend, Yahiko, die in his arms.

I mean, yeah, it doesn't get much more broken than that.

But a Death Note would mean little if our character was dumb, so let's give our villain the intelligence of someone.

Here, I've got the following villains in mind: Light Yagami, but we already used him, so he's out; Johan Liebert, Lelouch, Aizen, Makima, and Orochimaru.

Johan Liebert from Monster, his genius is terrifying because it's purely psychological.

Like it.

Eiji's right-hand man, Bud, is voiced by a guy I had the pleasure of meeting at San Japan, Nozomu Sasaki, best known as Tetsuo in Akira, Yusuke Urameshi in YuYu Hakusho, Johan Liebert in Monster, and Julian in Legend of the Galactic Heroes, among many, many others.

Speaking of Akira, and again, this is just me speculating, the character Akira is voiced by Mitsuo Iwata, who was Kaneda in Akira.

He is also most famous for being Kintaro in Golden Boy, Itsuki in Initial D, and Ivankov in One Piece.