The Great Other is the female other

[The Snark of Winterfell]

I'm sure that this has been posted before because I don't believe this is a groundbreaking theory so sorry about redundancy, if that's the case.

We now know that the Night's King is in the mix and is able to convert babies to white walkers or at the very least weigts.

The Knight's King Story:

According to legend, the Night's King lived during the Age of Heroes, not long after theWall was complete. He was a fearless warrior named the thirteenth Lord Commander of the Night's Watch. Later, he fell in love with a woman "with skin as white as the moon and eyes like blue stars". He chased her and loved her though "her skin was cold as ice", and when he gave his seed to her he gave his soul as well.

So we are pretty certain he slept with an Other and that made him what he is.

And we know there are or at least can be female others, even though only the male children of Craster are taken.

Melisandre refers to the Others as the "cold children" of the Great Other. ^[2]

We know that from the story that the female other is the one that converted the Night's King to the cold side.

So I think the Great Other is the female white walker described in the Night's King Story and ensures that she is the only female and operates like a Queen Bee and the Night's King is the King, but she has the power.