Yeah I’m inclined to agree with this if we define “evil” by destructive power at least (and always worth remembering that we merely have general agreements on what “evil” is, usually based on what is and isn’t considered advantageous for human well-being. Absolute good and evil are religious myths.). But GK was also kinda interesting in that his conquests etc. were “honest”. He wasn’t trying to build some ideal society, he just lived in accordance to “Might Makes Right” and surprisingly indiscriminately applied that into his domain as well. Whatever one could claim for themselves, was theirs so long as they could defend it. Regardless of gender, religion, further cultural details etc.

I feel like he represents the logical conclusion of non-conservative right-wing ideals taken to the extreme. Individual power (however that manifests - raw strength, charisma) trumps everything else, so in a way, libertarian… but everything was of course to be absolutely subject to the Mongol Empire rule so, authoritarian.

If we go by ideology + destructiveness as a metric of “evil”, probably Hitler.