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The book of secrets makes a character know a spell from the Lores of fire death or shadow. Does that mean they can use items meant for wizards? Like dispel scrolls, power familairs/spell familiars, power stones?
If a Million Guardsmen die, that's a statistic. If one marine dies, that's a tragedy.
Either that item is really poorly worded, or it doesn't make the character a wizard (in the same way as having a bound spell). Therefore, I'd say that it doesn't give said character access to the arcane items vault.