Tertia

The dwarven goddess, sort of. She is very mysterious at present, and the dwarves variously believe that she has died, abandoned them, or entered some kind of seclusion. Supposedly they do not worship her.

Tertia is mentioned by dwarven characters throughout the game. In particular, a dwarf at a shrine in upper Eustrin mentions that the party is free to worship whomever they wish at the shrine, and that "Tertia did not preach jealousy." The same dwarf says Tertia was goddess of "all the Earth, not just the rock" and implies that she should not be considered just a goddess of dwarves (that is confirmed later).

During a visit to Eustrin (chapter 5), the party finally meets her, but she is not what they were expecting.

Story
She is an old, really old entity (she describes herself as the "I am the goddess of the world itself"), but she remembers later that she wasn't present at the start (she can't even say if there was ever a truly beginning). That means that she has forgotten quite a bit of her own story (that includes her own origin, as she doesn't recall if she was mortal once or not). Taking that into account, she is able to fill some blanks about the Goddesses, the Incubus Kings and the relation between the shards (but it takes a while as she is weary, tired, and wish to be left alone).

Scenes

 * Tertia Titfuck – Simon and Tertia starts to explore how their relationship should work. Unmissable.