If only there were some place that had all sorts of rules all together, perhaps in book form. Oh wait! There is one.
"Unique characters with special abilities that have the same name and brigade are limited to a maximum of 1 each per 50 cards in a deck. For example, you can have one David (green brigade) and one David (red brigade) but not two David cards in the green brigade (even if their special abilities vary) in a deck that is smaller than 100 cards.
Generic characters with special abilities that have the same name and card art are limited to a maximum of 1 each per 50 cards in a deck. If the card art is different, you may select a maximum of 1 each per 50 cards in a deck from each variant. For example, you can have one of each of the black brigade Sadducees (4 Variants) cards in a deck that is smaller than 100 cards, provided they each have different card art."
Also, the REG, under Duplicate Cards:
"No player may control duplicates of a unique character or cause them to fight each other. This includes unique characters in play, in battle, in a side battle, face down, or in a set-aside area. Character cards with the same card title and the same art or with the same title and the same brigade are considered duplicates for deck building purposes. A player may have only control one of these at any time. The only exception to this rule is non-unique characters with different card art."
