Just as a little background: I've been playing the deck competitively since it was released in the TCG, and have been testing it since its OCG release. I try to play the deck at locals as often as possible, and while piloting it, I earned my invite to North American Nationals for the 2017 season. I also watch as many OCG Metalfoes duel videos as I can in order to improve my understanding of the deck's nuanced plays. I hope that my experience and familiarity with Metalfoes might help you build or improve your own deck.
The New Kid(s) on the Block
Invasion: Vengeance gave Metalfoes 4 new cards: 1 Main Deck monster, 1 Spell, and 2 Extra Deck monsters. Let's start with the Main Deck monster:
Raremetalfoes Bismugear is a Level 1 Pendulum monster with a scale of 8 and a statline of 0/0. He's got the same Pendulum effect as all the other Metalfoes monsters, but he also has something unique: a monster effect. If he is destroyed, you can activate this effect, which will allow you to add any Metalfoes monster from your deck to your hand during the End Phase. Activating Bismugear's effect does not directly lead to the search; instead, it's a declaration that you intend to resolve that effect later on. If you don't make that declaration at the right time (right after Bismugear is destroyed), you can't resolve the effect later during your End Phase. However, this goes both ways: your opponent can only negate Bismugear's effect when it activates, not when it resolves.
The value of Bismugear's effect is that it helps you set up plays and resources for your next turn. Since you don't choose the monster to add until the End Phase, you get to make your decision while keeping in mind everything that's already happened that turn. You might want to add a monster with the scale you'll need to continue your combos next turn, or simply a monster to use as backup Fusion Material.
One downside to Bismugear, however, is that he is Level 1 and thus cannot be Pendulum Summoned. This also means that, if he is destroyed, he cannot be revived each turn like your other Pendulum monsters. Moreover, his effect is hard-limited to one activation per turn, so destroying two of him in one turn won't net you any bonuses.
Run 1-2 (you can run a 3rd, but you should consider how your combo options will be affected by the increased risk of seeing multiples in your opening hand)
Next, we can look at the new Spell:
Fullmetalfoes Fusion is a Quick-Play Spell which allows you to Fusion Summon 1 Metalfoes Fusion Monster – nothing more, nothing less. I'm sure El Shaddoll Fusion comes to mind, but Fullmetalfoes Fusion doesn't carry the same hard once-per-turn restriction that El Shaddoll Fusion has. However, it's important to note that, just like any other Quick-Play Spell, Fullmetalfoes Fusion cannot be activated the turn it is Set, even if it is Set from your deck with a Metalfoes Pendulum effect.
So how does Fullmetalfoes Fusion play into the deck's strategy? Having the threat of fusing on your opponent's turn allows you to make any of your fusion monsters during your opponent's turn. This also means that the monsters being used as material can dodge effects that might've put you in a poor position. For example, if your opponent was hoping to banish your copy of Metalfoes Goldriver by targeting it, you can chain your copy of Fullmetalfoes Fusion and cause the banishing effect to resolve without effect by using Goldriver as a material. If you set up a Metalfoes Orichalc backed up by a Fullmetalfoes Fusion, you can turn your Orichalc into a trap as well as spit out another fusion monster. Having Metalfoes Combination in play allows you to generate advantage from it on either player's turn since you don't have to rely on your opponent being able to fusion summon. Playing 2 Fullmetalfoes Fusions naturally allows you to make 2 fusion monsters at Spell Speed 2, which can lead to some devastating combos with the new Fusion Monsters. This card's full utility will become clearer as I go over the new Fusion Monsters.
Run 1-2
The first new fusion monster is:
Metalfoes Mithrilium is a Level 6 Fusion monster with a statline of 2600/1000. Her Fusion Materials are 1 Metalfoes monster and 1 Pendulum monster. Mithrilium really does it all, and is without a doubt the most useful Metalfoes Fusion monster. Her first effect, which has a hard once-per-turn clause, allows her to target 2 Metalfoes cards in your graveyard and 1 card on either side of the field; the graveyard targets are shuffled back into your deck while the field target is returned to hand. This effect can be used to clear/bait your opponent's backrow or deal with their boss monsters. Mithrilium does all this while recycling your spent Metalfoes cards giving your scales new life and allowing you to set up elaborate strategies. Mithrilum can also recycle your other Fusion Monsters since her effect targets 2 "Metalfoes Cards" in your graveyard. Since you can target cards on both sides of the field as the third target, you can also bounce your own cards like one of your scales to use its effect again, or a Fullmetalfoes Fusion that was set during the same turn to push for damage. A small side note: if you target a Metalfoes Counter in your grave and that Counter is able to be banished, you can banish it in the same chain and still have Mithrilium's effect resolve even though only 1 card is returned to your deck.
When Mitrilium hits the grave, her second effect allows you to special summon a Metalfoes pendulum monster from your face up extra deck or graveyard, as many times as she is sent to the graveyard during the same turn. This also means that if you're going for a damage push with Fullmetalfoes Fusion, using Mithrilium as material turns results in 2 new monsters on the board, not just one. Playing 2 Mithrilium is absolutely staple, but playing a 3rd is definitely an option and is up to the deck builder. Your priority on recycling cards from the graveyard should always be the 2nd Mitrilium if it's in the grave, and is your last copy of Mithrilium. Metalfoes Orichalc can also revive Mithrilium through the effect of Metalfoes Combination, which is why some choose to not run the 3rd Mithrilium, beyond her first effect being a hard once-per-turn.
Run 2-3
The last new Metalfoes card and fusion monster is:
Fullmetalfoes Alkahest who is a level 1 fusion monster with a statline of 0/0. Alkahest is a very interesting monster whose Fusion Materials are 1 Metalfoes monster and 1 normal monster. Something that's important to keep in mind, Gofu Tokens can be used as the normal monster fusion material for Alkahest. Alkahest's first effect can only be activated during your opponent's turn. It allows you to target any targetable effect monster on the field and on resolution equip that monster to Alkahest as an equip spell, Alkahest gains its equipped monster's ATK as its DEF. Normal monsters can circumvent Alkahest's board pressure so be careful in the mirror match and against Blue-Eyes. Despite the caveats of only working on your opponent's turn, and not being able to go after normal monsters, Alkahest is one of the prime targets for Fullmetalfoes Fusion. A good combo to have under your belt is Orichalc and Fullmetalfoes Fusion on board. When your opponent activates a field spell or summons a key monster, chain Fullmetalfoes Fusion using Orichalc and a normal monster (or Gofu Token) as material to go into Alkahest. In a new chain, Orichalc will be able to target and destroy one of your opponent's cards while Alkahest will be primed to absorb an effect monster. This combo is susceptible to non-targeting and mass destruction, however, so it is often safer to leave a Mithrilium out on board since she replaces herself with another Metalfoes monster.
Alkahest's second effect allows monsters attached to him as equips to be used as Fusion Materials for a Metalfoes monster if they are the appropriate material. This effect can be very good, but can also be your undoing if you give your opponent a monster back that floats upon hitting the grave. It is also very important to keep in mind that if Alkahest is equipped with a union monster, he gains its union effect. Stealing an A - Assault Core will make your Alkahest immune to monster effects and prevent it from being destroyed and instead will destroy A. It's also imperative to acknowledge that Alkahest can only be special summoned by fusion summon. This means you cannot revive him from the grave by using Combination, do not forget this! If you ever want to use another Alkahest, it'll either have to be recycled by Mithrilium from your graveyard, or you'll just have to have a second copy in your extra deck.
Run 1-2
Last Words
Finding the space for these new cards might seem tough, but it's absolutely necessary if you'd like to take your Metalfoes deck to the next level. In my next post, I hope to actually talk about how a newer build might look with these cards, and how other engines effect the deck's playability and utility. As always I hope this was helpful, and feel free to leave any questions below!
