Originally Posted by Taon

I guess that depends on what happens if you fail the first attack; if you have to resummon the boss with full health then yes, you'd be wrong but otherwise no. I haven't failed yet, so I'm not sure how that works out.

The damage on the boss is permanent, so if you fail, your next attempt would be against a boss with considerably less health. (Last night, I accidentaly used my nation-battle unit against one of these bosses, and miserably failed, lol)