Which isekai has the best villains in your opinion?

For me it’s definitely Re:Zero just with the witches cult alone because:

1: They are genuine threats to the main characters and aren’t just used to show how strong the main characters are.

2: They are incredibly well written characters that range from incredibly vile to extremely sympathetic (Petelgeuse I was almost glad he got put out of his misery).

3: They aren’t just one off villains and they appear as a threat across multiple arcs and are the cause of many of the plot points in the series the most notable being Lye putting Rem in a Coma but only reappearing in arc 6 as the main antagonist.