She could just be a Verbena that uses snakes. You can have an evil seed in your heart and still have cool tattoos, a badass hoodie, and say "Nake, snake, cobra, cobrura".
You player will probably flip at the thought of sticking her feet in dirt to replenish her powers rather than eating frozen mice (or whatever), though. Since your player doesn't want to be a part of the World of Darkness as it is, your best bet might be to reshape it to suit her desires. Take the snake flavor away from ventrue, retcon the Verbena witch as something else (I'd go with
mi go; fill her with bees to pollinate her vines), and replace verbena with a cabal of
snake handers that sustain their powers though a constant high of venom (ritual power schedule, inject snake venom).
Snake Handler
Ritual power schedule, astral power source
Core discipline
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Veil of Morpheus: Enchanted Slumber, Dream Vision, Denial of Privacy (A).
Other disciplines
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Lure of Destruction: Tongue of the Serpent (probably euphoric).
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Auspex: Supernatural Senses
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Celerity: Quickness
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Presence: Dread Gaze, Majesty (A).
The base flaw could be disloyal, conspicuous consumption (
serious snake bites or needle marks), or even delusional (Pentecostal). You could also swap out the Veil of Morpheus stuff for Domination, including mesmerism. These guys should also probably get parseltongue (seriously limited feral whispers) for free.