Since the sequel is coming out 下一个 year, here are my personal opinions whether another character with snow powers will be feature in the sequel and whether 或者 not shall will be the protagonist 或者 the antagonist.

She should be the Antagonist

I would 爱情 to see Anna and Elsa having a wicked relative, who is actually their aunt and even has ice powers.But unlike Elsa's, their aunt's ice powers is 更多 powerful.
Her main motive is set the whole of Arendelle on ice permanently, unfortunately her powers were remove 由 sisterly love.

She should be the Protagonist

She was possessed 由 an evil spirit and as mentioned, Anna and Elsa help their aunt to eliminate the evil spirit that gave their aunt the ice powers, thus reconciliation between aunt and her 2 nieces through love.
My 秒 theory is that maybe she could be the 来源 for Elsa's powers, and since Elsa could control it, she is going to control her aunt's ice powers.


The Cold Never Bother Me Anyway!

So, here are my thoughts on whether the actual Ice 皇后乐队 is going to make her way into the sequel.