Deck identity, Chosen Champions, and hidden information

Two jobs sit in this lesson: building a legal deck, and knowing what each kind of information allows you to say or hide. For decks the key idea is the Domain Identity, the set of domains your Champion Legend allows. For information it is the privacy level of a card.

Worked example. You build around Ivern, Green Father, whose domains are Calm and Order, so your Domain Identity is Calm and Order (rule 103.2.b and rule 103.2.b.2). A card with one domain fits if that domain is in the identity (rule 103.2.b.3), and a card with two domains fits only if the identity holds both (rule 103.2.b.4). Your Rune Deck follows the identity too (rule 103.4.a.1). Your Chosen Champion must be a champion unit with a champion tag matching your legend, here Ivern. Daisy, a signature unit that also has the tag Ivern, cannot be it, because signature units are not champion units (rule 103.3.a.2 and rule 103.3.d.3). Daisy can still go in the Main Deck as one of your signature cards.

Deck limits. A card with no domain is permitted in decks of any Domain Identity (rule 103.2.b.5), and cards a game effect lets you add count as part of the identity (rule 103.2.b.6). A Main Deck can include up to 3 copies of the same named card, and this includes the Chosen Champion (rule 103.3.b and rule 103.3.b.1). Different names are different cards even for the same character (rule 103.3.b.2), but the same card printed in another language has the same name (rule 132.3). A deck may hold a sum total of 3 signature cards, whatever their names, all tagged for its legend (rule 103.3.d.1 and rule 103.3.d.2). When a deck needs more than one battlefield, it can't repeat a battlefield name (rule 103.5.c). The Core Rules ask for at least 40 cards in the Main Deck (rule 103.3), but in competitions it must be exactly 40 (TR 601.1.b). During play the Chosen Champion means the specific card chosen and any champion unit with the same name (rule 103.3.a.3).

Information. A card's privacy is the privacy of its zone unless its state says otherwise (rule 128.2.a). Secret means no player may look at the face, Private means only its owner or controller may, and Public means any player may (rule 128.3, rule 128.4 and rule 128.5). Cards in hand are Private. A player cannot be compelled to act on Secret or Private cards when the instruction names a type or quality of card, and may ignore it (rule 128.6). Showing Private information to another player is not revealing and does not trigger effects that care about revealing (rule 425.2.b). In competitions you must answer honestly any question about public information, must not misrepresent public or derived information, and may bluff about private information (TR 502.7, TR 502.8 and TR 502.11).

Deck rules at a competition. A unique sleeve on the Chosen Champion is allowed during setup, but it must match the Main Deck if the card would enter a private or secret zone (TR 422.2.b). A decklist with illegal elements, such as the wrong deck size or a card outside the legend's domains, is a Decklist Error and the penalty is a Game Loss, with the list corrected as little as possible (TR 703.3, TR 703.3.a.1 and TR 703.3.b.1). An illegal deck presented later is a Deck Presentation Error, a Warning, upgraded to a Game Loss if someone other than the erroring player catches it after opening hands are drawn (TR 703.4 and TR 703.4.c.3).

Common mistake. "I showed my hand, so it counts as revealed." It does not, and nothing that triggers on revealing happens.