Yes, for player-controlled units Quick Strike is optional. This means that if a Quick Strike
unit is grouped under another
unit that is defeated by a
spire, it can still
attack with normal timing because the timing for Quick Strike has passed. This is assuming the
unit on top of the
group did not itself use Quick Strike, in which case the next
unit in the
group cannot
attack that
turn because the
group can collectively only
attack once per
turn. AI-controlled units with Quick Strike will always choose to use it if possible. Again, if a Quick Strike
unit is
revealed after the Quick Strike timing has passed, it will still
attack with normal timing if it still has an
attack to make.
