I will especially the way you described kakuzu. You described him as if he wouldnt defend himself as if he really needs to. Destroying his hearts arent that simple unless he chooses to make it that simple. He has five hearts each he can just move to any length he wants from his body and still move fine.
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He shows in the top right panel that he can move his hearts within his hair/thread which can be stretched and shikamaru goes in debt with explaining that he cna chose to have all his hearts attack you.
I plan to just counter argue because i feel lazy.