Zatiel did not underestimate the person in front of him, even if it was just an incarnation made of energy and a thread of consciousness. Anyone with proficiency over the Law of Fate so high that he can intervene with Rank 4 life forms was a formidable individual.
More than once he has been in danger due to the actions of the Sage, and if he was any other person, he would have died.
He emptied his heart of all emotion and maintained a cool mind as he focuses on the grey figure. This will help him to make the best decisions possible.
He hugged the child with his hand and was ready to put him inside the spatial ring in case of any danger.
For how easily the incarnation was able to stop the bone sword, Zatiel deduced that its power should be very close to Rank 4.
The grey figure was also focusing on Zatiel and after a moment it spoke, with a robotic voice that gave no information about his sex and much less its identity.