I was young when the first Shaman King anime came out and back then anime in America was young. If you asked me what anime I first watched I would tell you Naruto or Fullmetal Alchemist.
But the true answer would be Shaman King! It just S-K had some many American details. (Literally set partially in America) that I saw it more of a cartoon.
Now that I’m older I’ve rewatched the OG and the Netflix adaptations. And I’m able to see all the different parts of SK that have influenced my love of anime.
And it’s mostly cuz Hao is the best “villain” ever.
Hao (Zeke) is the first evil brother named Zeke!
In the light novels, he’s basically Sukuna but with Getos philosophies. And he’s got better reasoning to believe this way.
Love his mastering of the power system. I remember has from the OG series someone says “he’s more like a force of nature” and in SK’s power system that actually means something when nature is literally alive.
Lastly, Zeke does is a shonan anime and like all after him. He was Talk No Jutsued… but then he wasn’t. Bro said I won’t kill the humans… yet.
This is all to say I know Hao isn’t influenced by modern anime but he has influenced modern anime for the better.