I don’t know how to really explain this but I think Miri is going to be Denji’s replacement- sent out in his stead & in his role while Denji is kept from Yoru’s field of view- on a narrative basis both in universe and on a story level.
“Miri as another version of Denji” is something that’s already been tackled narratively (down to his design, even) so I think this might be a culmination of that. He and Fami will be Denji and Asa’s replacements.

Thoughts?