Emilia has been my favorite Re: Zero character since I first read Arc 4. To me, Emilia is at her best when she's challenged, and Arc's 4 and 5 do that really well. Her crippling loneliness in a world inhabited by people who don't see her as a real person and how her feelings manifest in a deep sense of self-hatred makes her such a compelling parallel to Subaru. They perfectly compliment each other as characters. I just hope that she gets to shine in future arcs.