I don't really play hard games.
But I guess Nameless King from Dark Souls 3 was the hardest. I beat all the bosses without ember and I had to pop ember no matter what for Nameless King. And to be fair only the 1st half of phase 2 is the hard part. When 2nd half of phase 2 starts he leaves himself open to all attacks. I guess I may have been underleveled for him though.







