The Lockbox
The "lockbox" is a new feature on the card frame of character cards. Much like "class" symbols, it does not appear unless it applies to that character.
The lockbox on a character card indicates 1 or more brigades that the character's controller is restricted from playing on that character at anytime (in battle or territory). It is not a special ability (it functions like an identifier) so it cannot be negated and it resets to printed value anytime the character moves to a location that resets it (deck, discard, hand).
If a character has the same brigade in its brigade box AND in its lockbox, the Hero is still considered to belong to that brigade (for the purposes of things that target or count brigades) but enhancements of that brigade cannot be played on that Hero.
Example: The lockbox is shown on this Moses reprint above, right next to the brigade box (where the lock icon is). This card is "green locked" which means that you cannot play green brigade enhancements on him at anytime. His special ability, though, allows you to unlock green and lock either white or gold if you wish to when he enters battle (assuming he isn't being prevented). It only lasts this turn, though, after which he reverts back to green locked.
Enhancements with more than 1 brigade may still be played on a locked Hero if at least 1 unlocked brigade matches between the enhancement and the character. For example, you could still play Nunc Dimittis on the above Moses because both cards share the unlocked white brigade in addition to the locked green brigade, but you could not play Live Coal since Moses is locked to green and cannot play silver.
If a character with a lockbox is converted to a different alignment, the lockbox ceases to function unless the character is reset (even if they are converted back to their original alignment).
Pros of this mechanic:-A fairly simple addition to the card frame that resembles what it does and can be easy to explain
-Allows the use of lock/unlock abilities (such as with Moses above) to increase or decrease power temporarily for characters (such as an evil enhancement that locks a brigade for a turn as a block)
-Allows characters that should belong to multiple brigades to be given those while also limiting the power (such as with Moses above)
-Allows characters with many brigades to be given the rainbow brigade while limiting any brigades they shouldn't belong to (such as this card excerpt below of a multicultural human evil character that isn't specifically related to demons)
Cons of this mechanic:-It adds complexity to the game, players would need to know what the icon means
-It probably wouldn't be used on a lot of characters, just big names like Moses or very generic characters that could fit into multiple themes; so it may not be worth it