As many players know, "Darkness Approaches" is unique in that it's the only legal way to change a monster's position to face-down Attack Position (there's also an anime card that can do this, but it was never released in the TCG or OCG). However, as of March 25, 2017, its effect has been errata'd in the OCG, to change the target to face-down Defense Position.
Now, I have reason to suspect that this change was due to Link Monsters.
(Warning: Somewhat-long list, detailing both relevant rules regarding Link Monsters, and the rulings issues caused by the pre-errata effect of "Darkness Approaches" when used on Link Monsters. All mentions of "Darkness Approaches" in this list refer to the TCG/pre-errata OCG effect.)
- Link Monsters cannot be changed to Defense Position; this is likely to prevent the players from changing where their Link Markers point.
- If a monster is face-down, it has no properties until flipped face-up; it has no ATK or DEF, no effect (barring certain exceptions, such as double tributers always counting as 2 tributes even while face-down), no Level/Rank, no Attribute, no Type, and no name. By extension, this means that monsters lose their summoning information while face-down (and thus aren't considered to be Ritual, Fusion, Synchro, Xyz, or Pendulum). This would presumably apply to Link Monsters too, which would lose their ATK, their effect, their Link Number, their Link Markers, their Attribute, their Type, their name, and their status as Link Monsters. [Even if the monster was originally face-up on the field, it loses its properties if flipped face-down.]
- Because of #1 and #2, Link Monsters cannot be flipped face-down, for two reasons:
- Flipping them face-down, if possible, would allow them to be changed to Defense Position because they're no longer Link Monsters.
- All cards which flip a monster face-down change it to face-down Defense Position, other than "Darkness Approaches", meaning they don't affect Link Monsters anyways.
- "Darkness Approaches", as previously stated, is the sole exception to the trend mentioned in #3, as it flips monsters face-down without changing their Battle Position. and thus would be able to affect Link Monsters.
[This would also effectively remove its Link Markers, until it's flipped face-up again. The problem caused by this is detailed in #6.]
A monster's Battle Position can manually be changed once per turn, except on the turn that the monster is summoned or after that monster declares an attack.
- A monster can be changed from Attack Position to Defense Position, or vice versa.
- If a monster is in face-down Defense Position, it is flipped face-up when changed to Attack Position. If changed manually, this is called a Flip Summon, and counts as a flip, a position change, and a summon.
- Flip Summoning a face-down Defense Position monster is the only way to manually flip a face-down monster; otherwise, it must be attacked or an effect, an effect must be used on it that flips it, or an effect must be used on it that changes its position from Defense Position to Attack Position.
Thus, if a monster is in face-down Attack Position, it can manually be changed to Defense Position, without flipping it. This means that if a Link Monster can legally be changed to face-down Attack Position, it can be changed to face-down Defense Position, and then an effect can be used to flip it without changing its position (and, both because its position isn't being changed and because it's not a Link Monster while face-down, it won't be unaffected by the effect that flips it). This will have the end result that a Link Monster can indirectly be placed in face-up Defense Position, which is normally impossible.
Due to the new Monster Zone rules, Extra Deck monsters cannot be summoned to Main Monster Zones (the original 5 Monster Zones). If a Main Monster Zone is pointed to by a Link Monster's Link Marker, however, it becomes a Link Point, and Extra Deck monsters can be summoned to it (e.g., the Main Monster Zone directly below "Link Spider" is a Link Point, and an Extra Deck monster can be summoned to it).
If Link Monsters can be flipped face-down, Link Points become a rulings nightmare, specifically concerning Fusion Monsters. If I have "Link Spider" in an Extra Monster Zone, I activate "Polymerization" to fuse two monsters in my hand, and my opponent chains a quick effect that allows them to use "Darkness Approaches" or resolve its effect, then what happens? Possibilities include:
- "Polymerization" fails, as I cannot summon monsters from the Extra Deck. Fusion Materials aren't sent to the Graveyard, my Fusion Monster remains in my Extra Deck.
- "Polymerization" fails, as I cannot summon monsters from the Extra Deck. Fusion Materials are sent to the Graveyard, my Fusion Monster remains in my Extra Deck.
- "Polymerization" succeeds; however, I no longer have an Extra Monster Zone or any Link Points available, so it cannot exist on my field. Fusion Materials and my Fusion Monster are sent to the Graveyard.
- This may or may not count as being properly Summoned, and thus I may or may not be able to Special Summon it to a Main Monster Zone from the Graveyard.
- "Polymerization" succeeds; while I no longer have an Extra Monster Zone or any Link Points available, I did at activation. Fusion Materials are sent to the Graveyard, and my Fusion Monster can be summoned to the Main Monster Zone which was a Link Point when I activated "Polymerization".
- Due to all of the above, if "Darkness Approaches" was legal, it would be a rulings nightmare for Link Monsters, and the rules regarding them would need to state one or more of the following:
- Link Monsters cannot be flipped face-down, even if their position wouldn't be changed.
(This is the second simplest way to solve this, and is already implied by the rules. The only flaw is that it still leaves the possibility of "Darkness Approaches" causing other trouble in the future, and they're liable to forget about it considering how many cards they have to keep track of.)
- Link Monsters are considered Link Monsters even while face-down, which would prevent their positions from being changed while face-down.
(This would require that at least one of their properties not be hidden while face-down, which would conflict with the rules for non-Link face-down monsters. It also brings up the question of whether their Link Markers are still in effect while face-down, which ties into the Link Points rulings nightmare mentioned above; they presumably are, but this may not be the case.)
- Link Monsters aren't considered Link Monsters while face-down; despite this, their Battle Position cannot be changed if they're face-down.
(Due to the fact that face-down monsters have no properties, this essentially becomes an arbitrary "you can change this monster's position, but not that one's". As the face-down monster isn't considered a Link Monster, its Link Markers are no longer in effect; this brings up the Link Points ruling nightmare mentioned above.)
- If a Link Monster is flipped face-up, it is immediately switched to Attack Position; it is not considered to be in Defense Position at any point in time.
(This is the third simplest way to solve this, but it could cause issues if a face-down Link Monster is attacked.)
- Face-down monsters can be flipped from face-down Attack Position to face-up Attack Position without first changing them to face-down Defense Position.
(This would likely be considered a Flip Summon, but this isn't guaranteed. If it is, it would also bring up the question of whether Flip Summoning should still be tied to the act of changing a face-down monster's position.)
- Link Monsters are unaffected by "Darkness Approaches".
(While this seems simple at first glance, it has the problem of being tied to the card's name, and not its effect. Any card which changes "Darkness Approaches"' name will allow it to be used on Link Monsters. Any card which can resolve its own effect as "Darkness Approaches"' effect (such as "Serial Spell") will allow the effect to be used on Link Monsters, because it technically has a different name. Any card whose name is changed to "Darkness Approaches" by an effect will not affect Link Monsters, regardless of its actual name.)
- Link Monsters cannot be flipped face-down, even if their position wouldn't be changed.
Considering all of the above, the easiest solution by far is to errata the one card that can change monsters to face-down Attack Position, so that it always changes them to face-down Defense Position instead. This prevents it from affecting Link Monsters, preventing the aforementioned rulings nightmares.
Thus, my question is this: Considering the rulings issues that would be caused by allowing Link Monsters to legally be changed to face-down Attack Position, was the errata to "Darkness Approaches" intended to patch an otherwise-major loophole in the rules regarding Link Monsters?