(Mind you, not all MajalisArt posts are ToA related, but here goes)
Having examined the current art, as well as what Lore loose ends will most likely be resolved in Story Mode, it could be:
-Mermaid(Humanoid Form? But seems they've got balls in this pic so probs no)
-Fire Elemental (Same as above)
-A pre-demon Jester
-Cult Priestess
-
The legendary Shopkeeper Lewd
-Trudy's Former Travelling Companion
-The Hero we meet on the way to Zone 2 in Story Mode
-The Paladin of Drepnir
-The mysterious Adventure-Story Select Screen character in the middle, who appears possibly depicted on the Cult Temple Altar and has this(?) possible concept art. This is from an old image dump though.
If we're basing on skin-tone, I don't think it's the Warlock? Unless she gets a tan perhaps. Like I said, might not be ToA Art.