Ring of Maruf has an ~effect ~ that brings in cards from outside the game, so the way this is worded, it works

903.11

This rule has been updated to clarify that except via rules, special actions, and effects that specifically bring cards from outside the game into Commander games (such as the companion ability and rules), traditional cards from outside the game cannot be brought into Commander games.

This was the first one I saw.

I'm building that right deck then...
It's Warrior Wednesday!

You out here speaking truth!!!

Indeed, but my resolve is unwavering

Brian Canada, aka, Cure for the Common Game, the man with a thousand decks, lol.