After the book stopped shining, it landed on the bed before Gabriel.
"So I was right! You can understand me! You do have a soul!"
If Gabriel had a doubt before, he was now sure about this notion that the Grimoire actually had a soul, and it was intelligent. It could understand him and take action accordingly!
"No wonder you managed to take me to a safe place when I was about to die. You saved me at that time."
He was still grateful for the Grimoire, which saved his life twice. However, there were still some doubts in his head as well. If the Grimoire could take him to that bizarre place where he saw those statues, then why didn't the Grimoire of Darkness take the old owner there?
When the Lord of Darkness was surrounded by other Sacred Mages, then why didn't his Grimoire do the same? Why didn't his Grimoire save him? Was this something that only his Grimoire could do?