Then said Gangleri: "Which are the Ásynjur? Hárr said: "Frigg is the foremost: she has that estate which is called Fensalir, and it is most glorious. The second is Sága: she dwells at Søkkvabekkr, and that is a great abode. The third is Eir: she is the best physician. The fourth is Gefjun: she is a virgin, and they that die maidens attend her. The fifth is Fulla: she also is a maid, and goes with loose tresses and a golden band about her head; she bears the ashen coffer of Frigg, and has charge over her footgear, and knows her secret counsel.
Gylfaginning, Prose Edda
Mercy. Protection. Aid.
Eir is attested across two distinct roles in the Eddas and literature – that of handmaiden to Frigg, and that of valkyrie. In the former, she is called ‘the best of Physicians’, expert healer, proficient in offering aid. Presumably on hand in a role akin to a royal physician – though we can guess at the sort of ailments she may treat in that role.
In her potential role as a valkyrie, we can conclude that she would most probably act in a role similar to that of a battle medic. After all the valkyrjur (composed of the two halves "valr" and "kyrja") are ‘Choosers of the Slain’, choosing who lives and who dies. In the former, she may act to stop a life being taken too soon, binding wounds and the like. Naturally, then, Eir is often included frequently in modern Heathen practice – venerated and worshipped and worked with in all things to do with physical ailments, and for some, ill mental health.
For many too, she is a goddess seen as ‘being in the trenches’, hands stuck in to help people in all the ways she can. Some see her as something akin to an ER doctor, busy and inspiring modern physicians in turn to do their best work. To swiftly bring peace and wellness and happiness to those in need of it.