Fixed dice cannot be rerolled.
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If I use a skill to fix a die but my unit charges, what happens to this die? Do I have to reroll it?
Fixed dice cannot be rerolled.
What's the difference between a face-to-face roll between 'D' and the defense of the target unit and an attack?
When performing "an attack" (without specifying a roll) the attacking unit will use its profile attack (including modifier and switches). Meanwhile, in a face-to-face roll with 'D', since the unit is not using its attack, it can't use modifiers nor switches. In both cases, since it's using its profile defense, the target unit can use both modifiers and switches.