hyperadam
It's been a while, but I remember being very fond of Hawkfrost. I just like his appearance and his very manipulative style of villainy. He could be very sinister and charismatic, but also very smug and childish at times. That, and I really enjoyed his sibling relationship with Brambleclaw.
And I'm seconding the appreciation for Brackenfur I'm seeing in this thread. Whitestorm was also really cool. And Leafpool. I'm also starting the acquire a bit of a delayed appreciation for Hollyleaf, too…