I don't like the weird Binding advantage that Snake totems get, so I thought up an alternative. I think it works better in general, as snakes/serpents generally seem to be symbols of knowledge, rather than, um, Binding. So:
Mentor Spirit: Serpent
"Now the serpent was more subtle than any beast of the field
which the Lord God has made," -Genesis 3:1
Serpent is wise and cunning, a symbol of knowledge. Sometimes
a deceiver, sometimes a councilor, sometimes a seducer,
Serpent is always knowledgeable about what she counsels. An
avatar of truth whether counseling or even misleading, she
never tells an outright lie, instead using the truth creatively
to accomplish her aims.
Snake characters are obsessed with finding the truth, often
taking great risks to do so. They abhor lies and liars alike,
preferring instead to, "massage" the truth when deception is
necessary.
Advantages: +2 dice for Detection spells, +2 to Data Search Tests.
Disadvantages: –1 die on Con tests.
(Or, maybe even better: -1 die on all tests when telling or substantiating
a known, deliberate lie, until the falsehood is revealed or the lie is
no longer relevant. Note that half-truths are often not considered lies,
but can deceive nonetheless.)
How's that sound?