Can a player place a character card that does not match with the played character into the staging area as a foundation? Does it count as a blank text box foundation? Can Kazuya blow them up for his ability? Here is what happened. Kazuya player played a Kazuya card and brought it into his stanging area as a foundation. Next he played a Jin into his staging area as a foundation. He blew up the Jin character card for his ability.

Um. Creative, but completely fake rules.

2.1.12 When additional copies of a character card are placed in a staging area (See 4.3 Staging
Area), they are considered one card for the purposes of committing. (See 2.8 Ready &
Commit.)

2.1.13 When there are multiple character cards in a staging area (See 9.9), they are considered one
card for all effects, except those that specifically count or reference the number of
characters in play.

9.9 If the card is a version of the character card you are playing, it is moved to the staging area.

9.9.1 If the card is a character card with a name different than the one being played, it is placed
in the discard pile.

Yeah. Same characters get stacked, different ones get discarded. No foundation characters. No alternate Kazuya-fodder characters.

-Tinman

They also, as a note, don't move down as "foundations"... they just add abilities not already present on your character. So for example, if you start with Astrid and stack Astrid2, the additional Astrid will add the Good resource, as well as her two abilities. If you stack another Astrid, it will not affect her in any way after that point - the additional characters can't be committed separately and won't contribute abilities or resources you already have.