Necromancy?

[Deusteele]

The issue with Necromancy in FF XIV is that the lore behind it isn't; Corpse + Magic= Magically Animated Corpse.
But rather it is; Corpse + Local Equivalent to a Demon= Demonically Possessed Corpse.

Yes the first has voidsent. The gremlins are a kind of voidsent that may have hitched a ride with the Crystal Tower. I image all the shards have some problem with voidsent since all the shards are linked to each other.

In the larger lore of Final Fantasy Warriors of Darkness aren't uses of darker magics or other evil powers. They are Warriors who chose to stand against the power of Light when it goes out of control and threatens the world.

Edit: To be pedantic, we've been to the 13th shard. It was the final part of the Crystal Tower raid.