Do the Primals Know Each Other?

[Veritas-Ancora]

I still want to know how Iceheart is still alive. Gurl, when you go primal you never go back.

[Anonymoose]

I still want to know how Iceheart is still alive.

Based on the word choices of Minfilia, Nabriales, and Lahabrea, my assumption is that she used the Echo to make the walls of her soul permeable (the Echo seems to make your soul more sensitive and less rigid), thus allowing the, for lack of a better term, Essence of Frost to inhabit her by way of aether and prayer. She seems to have been able to prevent her spiritual form from being altered inn any way while still allowing herself to become a physical vessel, and then we beat that aether-enhanced vessel up until the essence withdrew, either due to expending the aether used to summon it, or by weakening Ysayle too much to be a suitable host.

Alternate Fringe Theory:
If Ysayle is fit to host Shiva, and Shiva was robust enough to lay with dragons...