What is The Eye doing?

[Lambdafish]

Can I mention that the Eyes have answered to THREE people at the same time?

Estinien, WoL, and Thordan.

Thordan didn't get chosen by the eye, he just used it as an aether fountain and a substitute for crystals when turning himself into a primal.

I'll give a good example: (3.3 story spoilers)

When primal used the power of Nidhoggs eye, he simply drained it of its aether, however when the WoL uses the power of hraesvelgrs eye they become "blessed" by it, enhancing his/her power, but in a very different way