14. Judge Renslayer - Loki
The four Disney+ live-action MCU shows so far have mostly got their villains right, but this character is easily the worst villain from any of these shows so far.
A member of the Time Variance Authority who does many awful things for the sake of the organisation, Judge Renslayer (Gugu Mbatha-Raw) had the potential to be an interesting and refreshingly human villain for the series. Instead, she's ridiculously dull and everything about her motivations and arc is predictable and one-note.
The highly talented Mbatha-Raw wasn't able to bring her to life, which is a testament to just how thinly written this character was. In the finale, she randomly disappears off to... somewhere, indicating that we haven't seen the last of her. What a terrible shame.
Still, Loki did a fine job with the main villain (who only appears in the finale) and it was a generally successful venture, so that's something.