Life of the Dragon implies you're tapping into Nidhoggs aether. BoTD imbued with Dravanian aether but we have never tapped into Nidhogg aether fully, despite being atuned to his eye from 30-69. Estinien gained the full gaze of Nidhoggs eye during the lv50 quest. It's assumed we gain his full gaze by using Dravanian power e.g. Mirage Dive.

Dragon Gaze allows you to impart a bit of this power to enhance you and your ally.

Nastrond is imbuing your Geirskogul (a release of concentrated Dravanian aether) with Nidhoggs.