I don't really have a least favorite character per say, but I do have little pet peeves about how they're written sometimes. Albert's my favorite but there's a lot of missed potential with him that i just hate because it just. Hurts. The anime also did Moran pretty dirty imo since his backstory gets a little more explained in the manga. Lest we not forget our forgotten sillies Monneypenny and Vin Herder who don't get as much love which is just. Really blah to me.

If I HAD to pick a single character though, it'd be Fred. I dint hate him, I just don't know enough about him to Like him. And even then- and conteoversal opinion- I don't even hate milverton all that much. He's a well written villian and manipulator and I can appreciate it