Because Metaphys Armed Dragon is a level 7 monster, when you activate Domain of the True Monarchs to lower its level it becomes a level 5 monster. Metaphys Armed Dragon also has some other unique features that I think are worth noting. This turns Brilliant Fusion into a way to activate all of your Monarch cards when you’re dry on literal Monarchs.
This means you can activate Brilliant Fusion, send Lazuli and Metaphys Armed Dragon, summon a Gem-Knight Seraphinite, then Lazuli will activate adding Metaphys Armed Dragon back to your hand. Gem-Knight Lazuli’s effect is that when it’s sent to the graveyard for a card effect you can add a normal monster from your graveyard to your hand. The most important of these is probably being able to activate Tenacity using it. This means you can use it to activate Tenacity, lower it’s level with Domain, summon it off Ehther, search it off Return, and recur it with Erebus. What’s incredibly crucial about this card is that it has 2800 ATK and 1000 DEF, the standard mega-monarch stats. Metaphys Armed Dragon is a Level 7 vanilla LIGHT Wyrm monster. But, by adding in Metaphys Armed Dragon there’s actually an even better LIGHT monster to dump from the deck. The immediately obvious card to dump off of Brilliant Fusion is Edea, since even when it’s sent from the deck to the graveyard you get to recur a banish Monarch spell or trap card. On top of that, when you also get to summon a Level 5 monster, Gem-Knight Seraphinite, that gives you an additional normal summon every turn. At the cost of running at least one copy of a mostly useless Gem-Knight monster, you get to run 3 copies of Foolish Burial for a LIGHT monster of choice. Brilliant Fusion has become sort of a combo staple card lately. With this engine you will more than likely want to be running at minimum a small Edea engine or 2 Edea and 2 Eidos or and engine of 2 Edea, 1 Eidos and 1 Mithra, whichever tickles your fancy more. I then eventually found a build running Metaphys Armed Dragon and this card all but completes the Brilliant Fusion circle! At first I thought the player running the Jack’s Knight was just trolling because why not? But then I realized he was also running Brilliant Fusion and then the pieces started falling in place as I thought of things this could do.
Eventually though I found a small amount of builds running Brilliant Fusion and either Jack’s Knight or Metaphys Armed Dragon. For the most part they were just normal deck lists, maining additional copies of trap cards, most now maining multiple Kuraz and 1 Escalation of the Monarchs as opposed to none. I noticed that despite the significant hits in the OCG on Monarchs a small handful of Monarch decks were still topping and I wanted to see what they were doing. The engine I’ve been testing originated in the OCG and I found it when scouring Japanese tournament deck lists. While at regionals though, I heard many murmurs of Patrick Hoban making some Brilliant Fusion Monarch deck and I figured he was just using the same idea I had been using, but when I finally looked it up when I got home I realized he was running, what in my opinion is, a much inferior version of the engine. Before the event I had toyed around with using an engine in Monarchs using Brilliant Fusion, but I decided I was far too unfamiliar with using it to effectively utilize it at a regionals, at least in a way I felt comfortable using. and that’s really all I have to say about my regionals experience. I went 5-3, I got to know the deck better and it’s strengths and weaknesses etc. I went on very short notice so I just grabbed the deck I new best being Artifact Monarchs. I just came back from the most recent Washington regionals. No, not the one that Hoban used, a different one.