Vevina Yarborough is a member of the Order of the Twin Adder in Final Fantasy XIV. She appeared earlier as well, but towards the end of version 1.x story she could be found in Jagged Crest Cave.
Quests
Grand Company quests
United We Stand (talk)
Scripts
(talk as a member of Maelstrom in Jagged Crest Cave)
Serpent Commander Yarborough: You are a soldier of the Maelstrom, are you not? Them I'm afraid I am not authorized to lend you my assistance. Ah, but pray do not mistake my intent - were the decision mine, I would have our organizations working in concert.