Um, the control metal can act as a mental link. Control metal's can be plugged into a host's brain. I think what we were seeing in vol 14 was a group of boosted creators useing the relic as an avatar. No creator was ever on Earth for the experiment. In the drawing, we never saw a metal shine of a control metal, just the circular lights to signify a control metal signal.
I meen, if the boost armor is a tool, wouldn't this be one way they would use it?
Yeah, I agree. But, since I can't read Japanese, you got to cut me some slack.