Kali. She only had 1 whole episode, and we barely know anything about her. I hope she returns for Season Five. I think she would be help to Eleven and the party, helping defeat Henry/001/Venca/Whatshisname. She was definitely one of my favorites in season 3, but not anymore since she doesn't show up after The Lost Sister episode.

I LOVE Kali and I really hope she comes back!! I feel like she could have a really interesting backstory considering she somehow got out of the lab and nobody ever tried to chase her down. I would love to see her experiences while still at the lab, how she got out, and what she did once she was out. I just feel that she is a character that they could do a lot with in the final season!

Kali went through too much, while Alexei knew what he got himself into when he agreed to help the Soviets open the gate

Alexei died

Kali her story is incomplete, if one of the two deserves more, it's Kali.

I have to go with Kali

I picked Kali because she was a unique character. Plus she is the "sister" to Eleven. I know The Lost Sister isn't everyone's favorite but I thought the episode was alright.

In addition Kali didn't get much screen time compared to Alexei

I feel like she needs to return to give her another chance to shine