Look, I have not played that many Pendulum Decks. Off the top of my mind, I've only played Supreme King, Odd-Eyes/Performapal, Solfachord, Dracoslayer (pre-DABL support), D/D/D (I've dipped my toes in there), and I have a lot of experience playing against Endymion. I've never played Metalfoes before, so I had to read all of their cards and look at what their combos were before attempting to make a Metalfoes Prediction Princess Deck. And to be fair, that really did not help because you can't really do Metalfoes combos in Prediction Princess. When you play Metalfoes, you should be playing Metalfoes. There isn't much room to stuff much non-engine or non-Metalfoes/Pendulum cards into the Deck and expect the Deck to function well or giving you consistent access to your plays. Metalfoes has 2 Level 9 monsters: Metalfoes Vanisher and Metalfoes Crimsonite. Vanisher is a Level 9 FIRE Psychic Scale 1 Pendulum Monster. Its Pendulum Effect allows you to add a Metalfoes card from GY to hand if a monster(s) you control is destroyed by card effect except during the damage step except for another Vanisher. Its monster effect allows you to target 2 face-up cards you control including a Metalfoes card and destroy them to Special Summon Vanisher from hand. And if it is Special Summoned by the effect of a Metalfoes card, you can target a monster your opponent controls or in their GY and banish it. Crimsonite is a Level 9 FIRE Psychic Non-Effect Fusion Monster that requires a Metalfoes monster and 2 monsters with 3000 or less ATK as Fusion Material. Vanisher is a pretty bad card for all things considered. You can't actually Pendulum Summon it in Metalfoes due to its Level and its effect is really whatever. And it is not like you can actually get it onto the field with Exceed the Pendulum either because she also is limited to monsters whose Levels are between your scales. As for Crimsonite, unless you are playing Super Polymerization, you are not playing this card. It is literally a vanilla that needs 4 cards invested to actually Summon it. So how are we going to be getting these 2 terrible monsters onto the field to target them with Monstrosity. Well, Pendulum Fusion is a card. It Fusion Summons using monsters you control but if you have 2 cards in your Pendulum Zones, you can also use them as Fusion Material. It's not the greatest thing, but it's all that we really have to make this work the way we want it to. So the goal is to use Pendulum Fusion to Fuse our Metalfoes scales and a monster we control to make Crimsonite. Or, if one of those scales is Vanisher, we can fuse just our scales to make Metalfoes Mithrilium and then Link it off to Special Vanisher from our face-up Extra Deck. You gotta do what you gotta do. To search for Pendulum Fusion and Monstrosity, we are playing our beloved Red Resonator Predaplant engine (it's just too good not to play). To make this work, we need Red Resonator, Predaplant Ophrys Scorpio, 2 Metalfoes Pendulum Monsters, and a monster to send to GY. Reminder: You gotta do what you gotta do. Normal Red Resonator and Special Summon Scorpio. Scorpio sends a monster from hand to GY to Special Summon Predaplant Darlingtonia Cobra from Deck. Cobra searches Pendulum Fusion. Synchro Red Resonator and Scorpio into Ib the World Chalice Justiciar who searches for World Legacy Monstrosity from Deck. Set your scales and activate Pendulum Fusion. Fuse your scales and Cobra to make Crimsonite. Activate Monstrosity to get Prediction Princess Bibliomuse and Deus-X Krawler from Deck. Xyz Crimsonite and Deus-X to make Mereologic Aggregator, sending Herald of the Arc Light, and it is the same old Prediction Princess combo from there. And since Ib is still on the field, you can use her and Aggregator to make I:P Masquerena. This Deck sucks. It's bad. It's terrible. I really dislike it. But, we are testing Level 9's for Prediction Princess here, so this has some merit to it. Like if I could find a better way to incorporate Pendulums into Prediction Princess, I would've done so already. The Pendulum Prediction Princess Deck I made a while ago that Summons Sorcerer of Dark Magic is pretty bad since you have to rely on drawing Monstrosity for one, but you also need to ensure that you have the ability to get 2 Supreme King Gate Magicians and have access to Timestar Magician as well. Like I even tried testing with Endymion (when I was trying to make World of Prophecy work - trust me, you are getting even more nowhere with that card), but since Servant of Endymion cannot Summon Frequency Magician, that was quickly scrubbed. Sometimes, these Level 9 experiments just do not work or don't come out pretty, but that is what we are trying to find out at the end of the day: whether or not this specific Level 9 can enable Prediction Princess plays as well as plays from their associated archetype or other kinds of plays from elsewhere.
For the monsters: 3 Prediction Princess Tarotrei, 1 Prediction Princess Tarotreith, and 3 Prediction Princess Bibliomuse. Tarotrei is a Quick Effect to flip a monster face-up or face-down and during the End Phase, she can Special Summon a Flip Monster from hand or GY face-down. Tarotreith can either be Ritual Summoned or Special Summoned via Tarotrei’s End Phase effect. On flip, she can Special Summon a Flip Monster from your Deck face-down and she can Quick Effect flip any number of your monsters either face-up or face-down. Bibliomuse can Special Summon herself back from GY face-down if she was tributed and sent there. On flip, she can add a Prediction Princess monster other than herself and a Ritual Spell from Deck to hand, and while she’s face-up on field, your Ritual Monsters gain targeting and destruction protection from your opponent’s effects. 1 Deus-X Krawler which negates all activated monster effects on your opponent’s side of the field after it has been flipped face-up and if it is destroyed on field, you can search for a Level 9 monster with a different Type and Attribute than it from Deck. 1 Pot of the Forbidden, which on flip, allows you to draw 2 cards, return all Spell/Trap Cards on field to the hand, destroy all monsters your opponent controls, or look at your opponent’s hand and shuffle a card of your choice back into the Deck. For the Metalfoes, 1 Metalfoes Vanisher, 3 Metalfoes Goldriver, and 3 Metalfoes Silverd. You can play any of the Metalfoes Normal Monsters you want. However, I would recommend playing the Level 4 or lowers together or playing the Level 5 or highers together and not with each other as it allows you to choose between playing Summoner’s Art for the Level 5 or highers or Painful Decision for the Level 4 or lowers. 3 Predaplant Ophrys Scorpio which sends a monster from your hand to GY on Normal or Special Summon to Special Summon a Predaplant monster from Deck and 1 Predaplant Darlingtonia Cobra which searches for a Fusion or Polymerization Spell from Deck if Special Summoned by the effect of a Predaplant monster. 2 Lonefire Blossom which can Tribute a Plant to Summon a Plant from Deck. 3 Red Resonator which can Special Summon a Level 4 or lower monster from your hand on Normal Summon or target 1 monster on the field on Special Summon to gain LP equal to that monster’s ATK.
Spell/Traps: 1 Instant Fusion for Master of Ham. 3 Underworld Ritual of Prediction which Ritual Summons a Prediction Princess Ritual Monster from hand or GY and you can banish it during the Standby Phase to Special Summon a non-Ritual Prediction Princess monster from Deck face-down. 1 Pendulum Fusion. 3 Pot of Prosperity. 1 World Legacy Monstrosity which either Special Summons a Level 9 monster from hand or targets a Level 9 monster you control to Special Summon 2 Level 9 monsters from your Deck with a different Type and Attribute than that monster but with different names. 3 Resonator Call which searches for a Resonator monster and 3 Painful Decision which sends a Level 4 or lower Normal Monster from Deck to GY and adds a monster with the same name from your Deck to your hand.
Extra Deck: 1 Trishula, the Dragon of Icy Imprisonment. 1 Metalfoes Crimsonite. 1 Metalfoes Mithrilium which Special Summons a Metalfoes Pendulum Monster from GY or face-up ED if it is sent from field to GY. 1 Master of Ham which can Special Summon a Flip Monster from hand or Deck face-down on Fusion Summon. 1 Ib the World Chalice Justiciar which searches a World Legacy card from Deck on Synchro Summon. 2 Herald of the Arc Light which searches for a Ritual Monster or Ritual Spell from Deck if sent to the GY. 1 Divine Arsenal AA-ZEUS - Sky Thunder. 2 Mereologic Aggregator. 1 Laevateinn, Generaider Boss of Shadows and 1 Jormungandr, Generaider Boss of Eternity. 1 S:P Little Knight and 1 I:P Masquerena. And 1 Gravity Controller.
Side Deck: 2 Nibiru, the Primal Being, 3 Thunder King, the Lightningstrike Kaiju, 2 Gizmek Kaku, the Supreme Shining Sky Stag, 2 Lightning Storm, 3 Dark Ruler No More, and 3 Evenly Matched.