Metatron

Drop Point: Is tethered to Haruyuki Arita/Silver Crow
Metatron is an A.I. that is one of the Legend Class Enemy of a higher class. She is bonded to Silver Crow and an honorary member of Nega Nebulas. She is aristocratic, uppity, and kind of a tsundere that easily gets angry with Haruyuki's careless actions though has a soft spot for him.
She calls the ones that deal in Brain Burst "little ones" due to her nature. Her true form on a higher level is one of a winged angel wearing something similar to that of a nun but white colored. Her eyes are closed yet she can see a typical anime troupe. Her form on the lower level where Brain Burst takes place is a bipedal snake-like being that is hard to defeat and when that form is beaten her true form is revealed with even higher difficulty that one should not fight.
Lore: She will be an observer and still aid Haruyuki and his crew. Everyone will see a small yellow icon floating around whenever she speaks.