Monster Removal
One of the most critical things to get right, since nine times out of ten, your opponent's win condition is monster-flavored. Adequate removal stalls your opponent and shifts the tempo to your favor. It's a straightforward topic, so this article is good for the uninitiated. Of course, there are plenty of competitive decks that skimp on removal cards or use bomb monster cards to do the trick--not every deck is Warriors and packs 10+ Traps, nor should they be--but regardless of what deck you pilot you'll need to be familiar with the tricks of the trade.
Straight Removal
Does it say "destroy"? Can you do it in your Main Phase 1? These kinds of cards might also be called proactive removal, removal that does not depend on battle in any capacity--removal that can be used as soon as it is drawn. Extremely aggressive decks benefit from their inclusion, as they can usually follow up and take out a good chunk of an opponent's LP. Not every card shown below is created equal, which is to say some, like Hammer Shot, are nigh unplayable. Offerings to the Doomed isn't fantastic but it is well balanced for what it is--a Quickplay threat-ender. Tribute to the Doomed is perfectly fair, but best suited to a deck comfortable paying for the discards, like Delinkquent's Zombie build. Nobleman of Crossout is a staple at two, and I've already gushed about Tribe-Infecting Virus, Smashing Ground, and Exiled Force in my Standard Chaos Warriors article. Dark Core has proven unpopular, despite checking several boxes for a removal Spell; this is also true for Back to Square One. The effect of both Chaos Sorcerer and Black Luster Soldier - Envoy of the Beginning should qualify them as removal, but they are instead classified as simply bomb monsters as they are not played so easily. Lightning Vortex relieves some pressure from Tribe-Infecting Virus, offering you another means of wiping your opponent's board.
Reactive Removal
Cards that have specific timings to activate or require certain conditions to be met, but still remove a threat from the board. Battle traps like Sakuretsu Armor all fit the definition, You'll want plenty of these, or a rock solid way to negate them, in order to survive the Warrior matchup. Bottomless Trap Hole and Michizure are both underwhelming. Widespread Ruin is an excellent backup Sakuretsu Armor that doesn't target. Counter traps that can negate summons, like Solemn Judgment and Horn of Heaven, can be counted as reactive removal also. Torrential Tribute and Mirror Force provide opportunities to gain card advantage over an opponent with their powerful effects, which is why they're staples unless running Royal Decree.
Flex Cards
Cards that can be played proactively or reactively to eliminate a threat, especially cards that have some other utility besides monster removal. Ring of Destruction is also a burn card. Raigeki Break can also destroy Spells and Traps. D.D. Warrior Lady answers almost any monster irrespective of its battle position and is a threat in her own right. Night Assailant also protects the hand from disruption while fueling cards that require discards for their costs. Cards like Newdoria and D.D. Assailant also fit the mold.
Pseudo-Removal
Cards that temporarily neutralize a threat, sometimes removing it from the board. Healthy for tempo but bad for card economy. Usually these cards have multiple possible uses. Book of Moon is a card with plenty, one of which is to flip a monster face-down during the battle phase to prevent an attack. Phoenix Wing Wind Blast can backfire but can also cripple an opponent, able to target any of their cards and hopefully set them back a turn of board development. Nightmare Wheel is able to target facedown monsters and is the best version of Spellbinding Circle in the format. Compulsory Evacuation Device can send a Thousand-Eyes Restrict back to the Fusion deck like PWWB, protect your monster from removal unlike PWWB, and it can hit facedown monsters too.
Theft
Monarch decks thrive on this style of removal, and it's growing in popularity. Snatch Steal speaks for itself. Brain Control is now standard sideboard tech thanks to the Warrior and Turbo Chaos meta. If you're running tribute monsters, you should scrutinize these cards. Creature Swap requires more support to pull off, benefiting from being in a deck with Scapegoat and recruiters like Mystic Tomato; even Spirit monsters like Asura Priest and Tsukuyomi have synergy with the card. Soul Exchange requires a dedicated build, usually, as the drawback of missing a battle phase requires the pilot to gain advantages in other ways.
Floodgates
Rather than remove monsters, why not just make them inert? Floodgates usually stick around to prevent your opponent from summoning or attacking, especially en masse. Cards like these give other archetypes a shot; Burn, for example. Other examples of floodgates in Goat Format include: King Tiger Wanghu, Gravity Bind, Thousand-Eyes Restrict, Wall of Revealing Light, Mirror Wall, Fairy Box, Royal Oppression, etc.
Threatlists
As part of deck construction, I like to think of every scary monster in Goat Format, and then wonder how I would go about removing them in the most efficient way. It helps to come up with a list of all the threats you expect to face, including probable sideboard choices, and all the answers you have for them. From there one can get a vague idea of how well prepared for battle one might be. As a general rule, it does help to diversify your removal sources along the lines of Monster, Spell, Trap; it also helps to diversify your removal types. Assume that if your opponent could run three copies of a good card, they would, unless it would lead to absolute bricks. Better to overestimate the opponent's threat density and be prepared, than underestimate it and get blown out. In this example, we will be dealing with speculative mainboards only for each archetype.
(3) Common Mainboard threats: BLS, Breaker the Magical Warrior, Tribe-Infecting Virus*. Three threats to account for, no matter the deck. *Some monsters are both threats and removal, or more accurately, are threats because they are removal and also have a battle phase.
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(9) Turbo Chaos threats: Chaos Sorcerer x3, Gravekeeper's Spy x3, Magician of Faith x3.
(10) Chaos Control threats: Chaos Sorcerer x3, Metamorphosis x3, Magician of Faith x3, Zaborg the Thunder Monarch.
(14) Warrior threats: Don Zaloog, Blade Knight x3, Kycoo the Ghost Destroyer x3, Ninja Grandmaster Sasuke x3, Mystic Swordsman LV2, D.D. Warrior Lady, Reinforcement of the Army x2.
(11) Panda Burn threats: Gyaku-Gire Panda x3, Injection Fairy Lily, Giant Rat x3, Des Koala x3, Cyber Jar
(11) Monarch threats: Monarchs x7, Sacred Phoenix of Nephthys, Metamorphosis x3. Monarchs aren't as standardized as other lists, so this estimate is a rough one at best.
(11)Reasoning/Gate threats: Chaos Sorcerer x3, Cyber-Stein x2, Dark Magician of Chaos, Jinzo, Airknight Parshath, Metamorphosis x3.
(9) Relinquished Control threats: Chaos Sorcerer x3, Relinquished x3, Metamorphosis x3.
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(5) Common Sideboard threats: Berserk Gorilla/Skilled Dark Magician x3, Mobius the Frost Monarch x2
Just some examples of what I'm talking about. Real duels don't last long enough for you to play (almost) every card in your deck like in Pokémon Base-Fossil, so keep in mind your opponent will not have time to drop all their threats. You generally want to have as many threats as possible, while accompanied by just enough removal to clear your opponent's threats. With initial overestimation, you may find in testing that some of your removal can be cut or sideboarded. Factoring in sideboard cards is an important piece of the puzzle that is usually best when informed by the meta you intend to compete in.
(3) Common Mainboard threats: BLS, Breaker the Magical Warrior, Tribe-Infecting Virus*. Three threats to account for, no matter the deck. *Some monsters are both threats and removal, or more accurately, are threats because they are removal and also have a battle phase.
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(9) Turbo Chaos threats: Chaos Sorcerer x3, Gravekeeper's Spy x3, Magician of Faith x3.
(10) Chaos Control threats: Chaos Sorcerer x3, Metamorphosis x3, Magician of Faith x3, Zaborg the Thunder Monarch.
(14) Warrior threats: Don Zaloog, Blade Knight x3, Kycoo the Ghost Destroyer x3, Ninja Grandmaster Sasuke x3, Mystic Swordsman LV2, D.D. Warrior Lady, Reinforcement of the Army x2.
(11) Panda Burn threats: Gyaku-Gire Panda x3, Injection Fairy Lily, Giant Rat x3, Des Koala x3, Cyber Jar
(11) Monarch threats: Monarchs x7, Sacred Phoenix of Nephthys, Metamorphosis x3. Monarchs aren't as standardized as other lists, so this estimate is a rough one at best.
(11)Reasoning/Gate threats: Chaos Sorcerer x3, Cyber-Stein x2, Dark Magician of Chaos, Jinzo, Airknight Parshath, Metamorphosis x3.
(9) Relinquished Control threats: Chaos Sorcerer x3, Relinquished x3, Metamorphosis x3.
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(5) Common Sideboard threats: Berserk Gorilla/Skilled Dark Magician x3, Mobius the Frost Monarch x2
Just some examples of what I'm talking about. Real duels don't last long enough for you to play (almost) every card in your deck like in Pokémon Base-Fossil, so keep in mind your opponent will not have time to drop all their threats. You generally want to have as many threats as possible, while accompanied by just enough removal to clear your opponent's threats. With initial overestimation, you may find in testing that some of your removal can be cut or sideboarded. Factoring in sideboard cards is an important piece of the puzzle that is usually best when informed by the meta you intend to compete in.
Removal Density
Let's take a look at the removal suite of Standard Chaos Warriors' mainboard to get a basis for comparison, since Warriors tends to run heavy on the removal side, this should give us an idea of what a deck ought to be packing to survive. You'll notice that the deck is about half removal.
Next we'll look at Turbo Chaos. Games 2 and 3 they should have access to multiple sideboarded battle traps. There is always debate between using Raigeki Break or Phoenix Wing Wind Blast, and we will not be settling that now. Break is generally better when run alongside Kycoo The Ghost Destroyer so as to deny opponents the use of monsters you destroy. Solemn Judgment has also been making appearances in main lately. Some might argue that D.D. Warrior Lady has no place in pure Chaos decks, but she's an important Sanganbox element and sometimes LIGHT for grave, so we'll include her. The same cannot be said for Tribe, whose specialization in clearing face-up monsters seems somewhat redundant with Chaos monsters, but I would caution against assuming its exclusion. This example suite is a little exaggerated intentionally for strategy discussion purposes.
Just for good measure, here's a breakdown of the removal inside a Chaos Control build that also runs Decree. The common Metamorphosis into Thousand-Eyes Restrict play doesn't show up on the radar here due to Meta's flexibility, so make sure to account for it.
We can check out the removal density of Samurai Soul Control too while we're here, a deck that relies on Royal Decree and Jinzo to keep monsters alive long enough to be tributed when the Theft Spells aren't an option. As you can see, this deck runs about half as much removal as Warrior or Turbo Chaos.
Finally, let's see how Panda Burn fares, to complete our cross-section.
So in a given 40 card Warrior deck, if about 20 cards are removal, about 10 cards are game winning threats, and about 10 cards are just for generating disadvantage for the opponent or advantage for the pilot. This holds true for the other metagame archetype leader, Turbo Chaos. If about 10 cards are removal, usually the deck is finding other ways to remove monsters, often through battle or the use of a Chaos monster which has so far mostly escaped note as a means of monster removal in this discussion. If your deck doesn't run a lot of removal or just can't get over in battle, carefully use your most powerful board clearing pieces like Mirror Force, Torrential Tribute, or Lightning Vortex.
Resisting Removal
What makes a monster hard to remove? Size is one factor, higher ATK and DEF generally means your opponent won't be gaining advantage over you in battle most of the time, but that is exactly why they run removal in the first place. So what else? Usually if the word "negate" appears in the effect text, that's when problems begin for your opponent--good luck using battle traps while Mirage Dragon is out. Monster effects that trigger in the graveyard to Special Summon monsters when they're destroyed by card effects are difficult to deal with; you can't even Solemn Judgment a Sacred Phoenix or Vampire Lord like you can a Jinzo. Chaos Command Magician seems designed to beat over Chaos Sorcerer and is immune to Thousand-Eyes Restrict as well, though the card has never been very popular due to how mechanically bad tribute monsters usually are by default. Of course the answer to everything but a Dark Balter the Terrible or Dark Ruler Ha Des or D.D. Survivor tends to be D.D. Warrior Lady since her effect doesn't target and does banish.
Breaking Boards
Some decks try to create board states that cover a very wide spectrum of removal options on their way to victory. Stein Gate decks have more ways than most to get out the venerable King Dragun, but I'd like to highlight the specific nightmare below, that I actually faced in GGP Avon, and how I *almost* managed to break the lock set up game one on my opponent's second turn (I persevered in games two and three through more luck than determination).
D.D. Warrior Lady and D.D. Assailant are your friends but are highly limited by their cost of one Normal Summon and dependence on the battle phase--a Tribe-Infecting Virus can clear it with less mess. Probably because of the grace with which it handles rough board states, Tribe is not searchable, but when Reinforcement of the Army gets turned off, it's kind of a moot point. I managed to get a D.D. on the board to clear a Horus the Black Flame Dragon LV8, but when it came time to drop Smashing Ground, my opponent had already summoned Dark Blade the Dragon Knight and Dragun remained intact. Diversifying your removal across Monster effects, Spells, and Traps reduces the likelihood that you can end up in lockdown--widening the scope of some of your removal tools also helps. Horus isn't really a metagame problem but it isn't unheard of either, so if you can resist it through clever deck construction, do so. Shoutout to Chase for the round 2 vibe check.
Conclusion
There isn't enough deck space to cram all the monster removal we want in there, and also attend to the other functions of a deck. This makes it challenging to decide what approach to take when dealing with our opponent's monsters. Conventional wisdom has settled on Sakuretsu Armor as the most satisfactory non-staple removal card, and you can expect to see many copies in play if you attend a tournament. Smashing Ground ought to be a close second but that distinction likely will belong to Book of Moon. If ever monsters start giving you trouble, find some room in your 55 for some more removal--there is a card that caters to your needs!
My Devil's Advocate
I don't want to construe my friend's argument here as being anti-removal. Removal is necessary, and you do have to draw it--meaning that running a somewhat high count of removal cards is important. The amount of removal needed though does seem to have a inverse relationship with the power of your threats. Can we make that observation in Goat Format, since so many threats function as removal? It's okay if the relationship between the two is a little blurry due to some monsters that pull their own weight.