I've long suspected that they were never going to use the Fortify mechanic because it seems like it is too hard to make a Fortification that wouldn't be better just being a plain old artifact. Some of what you've done with fortify seems good, but other cards strike me as falling victim to this problem.
For example, Mobile Outpost costs 2 to play and 3 to fortify, then you have to spend 3 and tap the land it is attached to to make a creature. If it were simply an artifact that cost 5 and had 4, T to make a creature, how different would that really be? I'll also point out that's a fairly weak card. I know that you could move it and use it twice in one turn, but that would cost 9 mana plus tapping two additional lands to do. Eleven mana to make two 1/1's doesn't add much to the card.
How much different is Intensity Matrix from an artifact that costs 2 and has "T: The next enchantment, artifact or creature you cast can't be countered."?
I like the ones that animate the lands into creatures, and I also have a soft spot for the ones that give the lands +P/T if they are creatures, but I think they are a little overcosted considering how narrow they are. Also it seems a little excessive to have a fortification that gives hexproof and another that gives indestructibility and another that gives protection from everything all in the same set. I understand these are very different on creatures but on a non-creature land they are very same-y.
I'm going to try to come back and take a look at the rest of the set later, I just jumped to the artifacts first because this was a mechanic I didn't see a lot of potential for. I was pleasantly surprised to see that some of the ideas were really neat, though.
When Shadow Leech dies return it to play as an Enchantment - Aura with "Enchant a Swamp you control", "At the beginning of your upkeep you lose 2 life." and "Whenever enchanted swamp's controller taps it for mana, that player adds BB to his or her mana pool."
OR
If Shadow Leech would die instead it becomes and Enchantment - Aura with ... Attach it to a Swamp you control.
I think for Korus it is just incongruous to have a creature cost UUURRR and destroy non-basic lands. That casting cost is brutal, but it is especially brutal if you are playing non basics. Basically with the drawback he effectively costs 8 at least, or he really costs six but destroys three of your lands when he comes into play. He is quite underpowered for either of those casting costs.
I would not use the name "Nyarlathotep" for a 2/2 that people wouldn't be inclined to play outside of limited. Nothing against the card you designed, which is has a nice Lovecraftian bent to it, but I don't think that name is appropriate.
Your idea attempts to capture the chaos that is associated with Nyarlathotep, but doesn't do justice to Nyarlathotep's power (he is feared by gods) and it doesn't capture the fact that he takes on many forms (which is about the only thing we know about him).
If I was going to design Nyarlathotep as a magic card, I would be strongly inclined to make him a planeswalker. There are a couple of reasons for this. The Eldrazi, which are native to the Blind Eternities and able to travel to various planes are clearly references to Lovecraftian horrors. The very fact that the space between planes is called the "Blind Eternities" is itself a sort of Lovecraftian nod. Azathoth, in Magic terms, would not be an entity that existed on one plane, but rather the essence of or "god" of the Blind Eternities themselves. Nyarlathotep is the herald of Azathoth, and the closest thing to Azathoth that a mortal could glimpse or begin to comprehend.
In the spirit of the Nyarlathotep presented in Lovecraft's "Nyarlathotep", "The Dream-Quest of Unknown Kadath", and "The Dreams in the Witch House" I would present Nyarlathotep something more like this (and borrowing from your great idea):
Nyarlathotep, the Crawling Chaos7
Planeswalker - Nyarlathotep
[+4] Flip a coin. If you win, exile target permanent, otherwise exile a permanent you control.
[-3] You and target opponent each choose two permanents that opponent controls. Flip a coin, if you win exile the permanents you chose, otherwise exile the permanents your opponent chose.
[-12] Nyarlathotep becomes a copy of an exiled creature card except that he is indestructible, gets +8/+8, trample and "Annihilator 6".
{7}
Once you get to 8 I don't think it's really worth a discount in mana cost at all. Not being able to get Iona in older formats is a limitation, but contemporary reanimation decks are reanimating titans and Elesh Norn. Three mana is very cheap for that.
Now I really like the idea of a two or three mana reanimation spell that does a single specific casting cost, but obviously it would have to fit into a set where there were plenty of targets at that cost.
Bowden's Malady is very rarely anything like a 4 for 1. You're casting an 8 mana sorcery, so let's assume your opponent just cast a 6+ mana creature.
First of all - do they even have any cards in their hand?
Second - is sacrificing a land setting them back?
Third - suppose that creature is a Titan, Elesh Norn, or Sheoldred... is that 4 damage to one of their creatures helping you win this game?
8 mana sorceries need to have exceptionally powerful effects. If you want to stick with similar effects, I would say they discard two cards, you destroy up to two target lands and up to two target creatures. Maybe throw some damage in their face as well.
Cranial Incision is fantastically underpowered. If you multiplied the effect by five (that is, remove five cards and mill for the total) then it would at least look appropriately powered, even if it would still be a pretty unplayable card.
The problem is you are paying 8 mana for a 4/4 flier with a drawback. Or you are paying 8 mana and two cards for an 8/8 flier that can be blocked by a 2 mana flier. Or 8 mana and three cards for a 12/12 flier that is still very easy to stop.
For 8 mana I expect a creature to have a good chance of winning me the game even if I am already at a very considerably disadvantage. For 8 mana and three cards I expect a creature to be nearly unbeatable.
I think it costs a little too much for its power level even without the drawback. With the drawback I can't see an appropriate cost for it. The drawback is just incredibly swingy - especially with Devour.
The card as worded would not work out the way you want. It would enter play as a copy of another creature and if it transformed, it would still just be a copy of the creature it entered play as (the same thing would happen if you used a card that turned your werewolf into a copy of another creature - if you transformed it, it would still be the copy of the other creature).
The effect should say, "You may have ~ enter the battlefield as a copy of any other creature on the battlefield. This effect lasts until ~ transforms." or something similar.
I also think it would be better if his power became the greatest power and his toughness became the greatest toughness among creatures.
I think this card might be a little bit complex for how often it's effects would actually come up.
To avoid the errata for every card that references the library issue, the card type should be "Archive", not "Library" and simply put in the rules that when you do something to a players library you can choose to do it to one of their archives instead (similar to how direct damage to planeswalkers works).
That being said, it's only worth a new card type if these are going to be appearing in set after set and block after block. This looks like a single block mechanic. Because of that, I like lifeinsepia's implementation - though I'd be very tempted to make them artifacts instead of enchantments.
Whenever you make a hybrid spell you really have to check if the effect is appropriate for a mono-coloured deck. 1RR for discard two random cards just doesn't seem red.
I don't think Traumatic Screams is too powerful: odds are it isn't really useful at all. In order to say it is too powerful, we should be able construct a plausible situation where it would be used to win the game. Are we doing so by milling out your opponent's entire deck? If so, how much life did you gain and what turn is it to enable that victory? I think the answer is that you've gained 20+ life and it is turn ten. That does not make an overpowered card.
Imagine a "perfect draw". If you play first you need to mill them for 54 - your turn number (so 53 on turn one) to win. So you need to gain 34 life by turn one, 33 by turn two, 32 by turn three, etc.
32 by turn three is possible in vintage with a ridiculously improbably draw, but goldfishing turn three in vintage isn't remotely impressive. I think gaining 30 life by turn five in standard may be doable, but it's a pretty easy win condition for your opponent to attack. If they manage to do a couple of damage to you then you don't win. If by turn five you are at 50 life it suggests your opponent hasn't been doing anything, which means they aren't an aggressive deck, which makes me pretty confident they can counter one card to stop you from winning. Even then, winning goldfishing on turn five in standard is no very impressive either.
It could be a cheap kill card for an infinite life combo deck, but nasty creatures also serve as kill cards for those decks and have big advantages over a card like this: 1) they do something if you didn't pull off infinite life; 2) once you've used your infinite life combo you usually aren't in a desperate rush to win anyway.
It is completely true. This doesn't counter spells they already cast, nor does it stop them from using leftover mana that you didn't use while you controlled them. But someone definitely can't respond to you casting this card in any way.
You declare you are casting it, you put it on the stack, you pay costs, you control them. They can't play instants or activate abilities to use their mana in response because from the moment you said you were going to play if you controlled them.
For example, Mobile Outpost costs 2 to play and 3 to fortify, then you have to spend 3 and tap the land it is attached to to make a creature. If it were simply an artifact that cost 5 and had 4, T to make a creature, how different would that really be? I'll also point out that's a fairly weak card. I know that you could move it and use it twice in one turn, but that would cost 9 mana plus tapping two additional lands to do. Eleven mana to make two 1/1's doesn't add much to the card.
How much different is Intensity Matrix from an artifact that costs 2 and has "T: The next enchantment, artifact or creature you cast can't be countered."?
I like the ones that animate the lands into creatures, and I also have a soft spot for the ones that give the lands +P/T if they are creatures, but I think they are a little overcosted considering how narrow they are. Also it seems a little excessive to have a fortification that gives hexproof and another that gives indestructibility and another that gives protection from everything all in the same set. I understand these are very different on creatures but on a non-creature land they are very same-y.
I'm going to try to come back and take a look at the rest of the set later, I just jumped to the artifacts first because this was a mechanic I didn't see a lot of potential for. I was pleasantly surprised to see that some of the ideas were really neat, though.
When Shadow Leech dies return it to play as an Enchantment - Aura with "Enchant a Swamp you control", "At the beginning of your upkeep you lose 2 life." and "Whenever enchanted swamp's controller taps it for mana, that player adds BB to his or her mana pool."
OR
If Shadow Leech would die instead it becomes and Enchantment - Aura with ... Attach it to a Swamp you control.
Your idea attempts to capture the chaos that is associated with Nyarlathotep, but doesn't do justice to Nyarlathotep's power (he is feared by gods) and it doesn't capture the fact that he takes on many forms (which is about the only thing we know about him).
If I was going to design Nyarlathotep as a magic card, I would be strongly inclined to make him a planeswalker. There are a couple of reasons for this. The Eldrazi, which are native to the Blind Eternities and able to travel to various planes are clearly references to Lovecraftian horrors. The very fact that the space between planes is called the "Blind Eternities" is itself a sort of Lovecraftian nod. Azathoth, in Magic terms, would not be an entity that existed on one plane, but rather the essence of or "god" of the Blind Eternities themselves. Nyarlathotep is the herald of Azathoth, and the closest thing to Azathoth that a mortal could glimpse or begin to comprehend.
In the spirit of the Nyarlathotep presented in Lovecraft's "Nyarlathotep", "The Dream-Quest of Unknown Kadath", and "The Dreams in the Witch House" I would present Nyarlathotep something more like this (and borrowing from your great idea):
Nyarlathotep, the Crawling Chaos 7
Planeswalker - Nyarlathotep
[+4] Flip a coin. If you win, exile target permanent, otherwise exile a permanent you control.
[-3] You and target opponent each choose two permanents that opponent controls. Flip a coin, if you win exile the permanents you chose, otherwise exile the permanents your opponent chose.
[-12] Nyarlathotep becomes a copy of an exiled creature card except that he is indestructible, gets +8/+8, trample and "Annihilator 6".
{7}
Now I really like the idea of a two or three mana reanimation spell that does a single specific casting cost, but obviously it would have to fit into a set where there were plenty of targets at that cost.
First of all - do they even have any cards in their hand?
Second - is sacrificing a land setting them back?
Third - suppose that creature is a Titan, Elesh Norn, or Sheoldred... is that 4 damage to one of their creatures helping you win this game?
8 mana sorceries need to have exceptionally powerful effects. If you want to stick with similar effects, I would say they discard two cards, you destroy up to two target lands and up to two target creatures. Maybe throw some damage in their face as well.
Cranial Incision is fantastically underpowered. If you multiplied the effect by five (that is, remove five cards and mill for the total) then it would at least look appropriately powered, even if it would still be a pretty unplayable card.
For 8 mana I expect a creature to have a good chance of winning me the game even if I am already at a very considerably disadvantage. For 8 mana and three cards I expect a creature to be nearly unbeatable.
I think it costs a little too much for its power level even without the drawback. With the drawback I can't see an appropriate cost for it. The drawback is just incredibly swingy - especially with Devour.
The effect should say, "You may have ~ enter the battlefield as a copy of any other creature on the battlefield. This effect lasts until ~ transforms." or something similar.
I also think it would be better if his power became the greatest power and his toughness became the greatest toughness among creatures.
I think this card might be a little bit complex for how often it's effects would actually come up.
That being said, it's only worth a new card type if these are going to be appearing in set after set and block after block. This looks like a single block mechanic. Because of that, I like lifeinsepia's implementation - though I'd be very tempted to make them artifacts instead of enchantments.
Very overpowered. Restricted in Vintage, banned in legacy, very dangerous in contemporary formats.
Imagine a "perfect draw". If you play first you need to mill them for 54 - your turn number (so 53 on turn one) to win. So you need to gain 34 life by turn one, 33 by turn two, 32 by turn three, etc.
32 by turn three is possible in vintage with a ridiculously improbably draw, but goldfishing turn three in vintage isn't remotely impressive. I think gaining 30 life by turn five in standard may be doable, but it's a pretty easy win condition for your opponent to attack. If they manage to do a couple of damage to you then you don't win. If by turn five you are at 50 life it suggests your opponent hasn't been doing anything, which means they aren't an aggressive deck, which makes me pretty confident they can counter one card to stop you from winning. Even then, winning goldfishing on turn five in standard is no very impressive either.
It could be a cheap kill card for an infinite life combo deck, but nasty creatures also serve as kill cards for those decks and have big advantages over a card like this: 1) they do something if you didn't pull off infinite life; 2) once you've used your infinite life combo you usually aren't in a desperate rush to win anyway.
It is completely true. This doesn't counter spells they already cast, nor does it stop them from using leftover mana that you didn't use while you controlled them. But someone definitely can't respond to you casting this card in any way.
You declare you are casting it, you put it on the stack, you pay costs, you control them. They can't play instants or activate abilities to use their mana in response because from the moment you said you were going to play if you controlled them.