Quote Originally Posted by HaelseMikiro View Post
An old despair astride a new-shod mare.

I'd interpret that either as 'the primal threat' with Shiva simply being the newest incarnation of it (also we expect her to drop a new horse)
or
less likely it's Lahabrea with a new physical host
We're getting Shiva in 2.4, so why refer to her when she's being released so soon? They already referred to Shiva in a previous poem.

However it has been hinted that she is behind the Dravinian Heretics in Coerthas...so maybe? Dravinia is at war with Ishgard, so it certainly fits.