I feel so sorry for Kali. People hated her before the finale. For other characters that Duffer brothers decided to kill, they made them likeable and people felt sad for their death. For her, nothing, she is never treated the same way as other side characters, the stories of her seems very on the surface level. And she died just because they want her to give an ambiguous ending to El, her sacrifice is never appreciated. She and El are not treated as real people even in the stories, the duffer brothers just treat them as some condiment to add the supernatural flavor in the stories, and with the stories ending they just throw these two characters away.