Aura

Aura, translated from 「アウラ」 in Japanese, is a Goddess of Light mentioned in the instruction manual of Famicom version of Dragon Quest I and Dragon Quest II. She seems to be a very important person, but she doesn't appear in the game at all, nor is she mentioned.

Dragon Quest I
Aura's identity is completely unknown except that Holy Water is imbued with her blessing. Aside from that, she does not make any other appearance and is not even referenced in the Dragon Quest series since. She does not even appear in Dragon Quest XI, and not even Dragon Quest Builders where characters like Rubiss and Mahetta (the latter who had seemingly been forgotten until Dragon Quest Builders) make an appearance. Aura seems to have been completely forgotten.

It bodes the question as to whether she is related in some way to Rubiss, who is the Spirit of the Earth (or Goddess of the Earth), as Aura is the Goddess of Light. This may mean that she has some relation to Sphere of Light and therefore will have relations to characters like the Dragon Queen and Yggdragon.