How does WoL maintain Azure Dragoon powers if that power comes from Nidhogg Eye

DRG quests 30-50 reveal that Azure Dragoons are a cut above regular Dragoons and can perform more powerful feats that require channeling of Aether via Nidhogg's Eye (e.g. Dragonfire Dive). After the events of defeating Shinryu in Stormblood, both of Nidhogg's eyes are annihilated by Estinian, yet he and we presumably maintain our Azure Dragoon powers. How? Moreover, Life of the Dragoon seems to be a channeling of specifically Nidhogg's Aether, as Nastrond seems to be a Geirskogul that's steeped in his crimson Aether.

I'm going to dig a bit, but so much aetherial phenomenon turns out to be left-over traces of "waveforms" left imprinted on things or resonating with things that somewhere between Nidhogg, the Eyes, the descendants of Ratatoskr's killers, the HAX blessing of the Mothercrystal, and the soul crystals, there's something that could be used to hand-wave this.

there's also middy who is seemingly always with us even if he doesn't show up very often. as for est he was possessed by nidhogg for a while so some of nidhoggs aether might have rubbed off on him in a similar manner to SMN egi's.