Board Thread:Naruto Discussions/@comment-33953813-20171222191100/@comment-27924662-20171223074558

Gagua2028 wrote: Blue B did have control over it but it was just like Naruto. He said he didn't have that thing "to fill the hole in his heart" and that's why he couldn't sleep on full moon nights or some days when the Gyuki's power was strong enough to take control over him.

We know that Bee could fill "the hole in the heart" by the words that A said to him. that was week before his death. He died because he couldn't control Gyuki, But it seems Gyuki was much more reasonable. even Raikage couldn't believe that he was having trouble in controlling the beast after all those years.