Page 17: Sinai said "I will excuse myself", after he parted ways with Shiki and Kuzunoha, and while entering the room to have an audience with the Bishop.
Should that not have been a simple "Excuse me"?
Ranks and name spelling has been pretty inconsistent in this chapter.
I presume that the weapons were manufactured using the bodies of those whose cossuption rate hit max. Mutated, subdued, and used as breeder reactors to make them.
From context and the chant, it's probably a condition to strengthen the spell, like GoMyTeam said. Ritual magics in many samples of fantasy require spell components, certain kinds of mental, and sometimes emotional focus, so his deprived state in itself is a kind of component for the ritual...
"S-She looks strong..."
She also looks like she's out of her mind.
Best case, my guess is either from whatever slave device or contract was used. At the worst, we have an incoming psycho.