Board Thread:General Discussion/@comment-24189673-20131222191208/@comment-8986886-20131222192444

The "monster" that Yamamoto spoke of, was probably Yhwach. At least that's the impression I got while reading it. Yamamoto believed that if he ever saw that monster again, it would almost certainly mean his death. Since Yhwach's return brought the death of Yamamoto, it confirms his past prediction.