Due to trademark issues, Pentagon Jr. had to change his ring name while working for AEW.
Dave Meltzer reported in the latest edition of the Wrestling Observer Newsletter that “Pentagon Jr. is now Penta Cero M. That's the name he owns merchandising rights to.”
It was noted that AEW was allowed to use the Pentagon Jr. name because they had a working relationship with AAA, which owns the name. However, All Elite Wrestling pushed for the name change because of a variety of potential projects that they have planned by marketing him.
It was noted that his tag team partner, Rey Fenix, owns that name but not just Fenix, which AAA owns. He's been Rey Fenix in AEW from the start.
Meltzer stated that once AEW started merchandising the tag team the promotion didn't want to use an AAA-owned name and at some point they were going to switch it to a name Pentagon Jr owns and it was just a question of when.
It was added that the name also coincides with the Masked Republic deal getting Penta Cero Miedo merchandise into Hot Topic.