In the way that it says it
He discover that he might suffer from some mental disorder causing him to react aggressively and with no limits at all,suffering afterwards from the aftermath of his own actions therefore he decides to keep a journal about it for research....
Where is the following statements
The answer is letter C.Grendel's Mother
Grendel's mother is one of the antagonists of Beowulf. She is known to be one of the descendants of Cain. She had attacked Heorot as a form of revenge. Beowulf had tried to kill her as he went to her cave with the hopes to kill her.