If you align your troops in these positions in the character inventory (X indicating a position occupied by nobody):
X*******X
X*X***X*X
In an ensuing battle, they are actually positioned like this:
X*******X
XX*X***X*X
That is, one of the backliners (directly behind a frontliner on the left side of the formation as shown in the character inventory) is positioned one space to the inside of the applicable frontliner once battle begins, and another of the backliners (directly behind a frontliner on the right side of the formation as shown in the character inventory) is positioned one space to the outside of the applicable frontliner once battle begins. So it looks like any empty spaces to the left of the frontline in the character inventory are deleted once battle begins.
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