The Forbidden Arts/ "The Pure Evil" from The Swan Princess. Reason why it does not count is moral agency issues as it is otherwise definitely heinous enough and it has no redeeming qualities.

Broly is one I know. Hyde I believe was identified as one.

Well, Tengu Shredder was called the greatest evil known to the world in the second TMNT cartoon, but his imposter did worse with fewer resources.

“You dare call ME an imposter?”

I remembered when Grandfather (KND) was one.