It's most likely that Estinien will be back in the nick of time to save the WoL and co. from who ever is using the eye. In fact, I think he'll be back by 3.5 telling us that he still senses Nidhogg's eye. By then end, I'm sure Estinnien will take the eyes back and go to a faraway place to guard them like he was originally planning in 3.0