This is the cheapest and most efficient way to make all your creatures ninja's. This is probably the most tutored for card in the deck. It allows your unblockable 1 and 2 drops to hit for Yuriko triggers without any Ninjutsu or work on your part. With this enchantment out it can become trivially easy to hit with three or four ninjas early in the game to deal huge amounts of damage to the whole table. There are 3 other cards in the deck that act as backup copies of this card and I'll put them in order of best to worst.
Unnatural selection is the second best 'turn your stuff into Ninjas' card because its cheap and easy to tutor for, even the transmute cards get it. It's also less threatening on the table than the static enchantments because you have to spend mana to use it, but our stuff is so cheap its deceptive how little that matters. Consipracy is next because it effects Ninjas in your hand or library just like Arcane Adaption, so
Higure, the Still Wind
can tutor for any creature in your deck. The worst version of this effect is Xenograft and is only in the deck because the effect is so needed. Doesn't hurt that it does 5 damage off a Yuriko Trigger.
This card is an all-star in the deck. I have a pretty strict $20 dollar limit when buying cards but I had to break my rule to add Scroll Rack to this list because of how important it is for this deck to run smoothly. If you are looking to build this style of Yuriko deck having this card is not optional. You can tutor for it with all the tutors in the deck including the transmute cards. Scroll Rack paired with Arcane Adaption can very easily end the game in a single turn. One of the biggest problems with Yuriko decks that try to kill with large spells is not flipping them with Yuriko's trigger but instead drawing them naturally, where they sit uncastable and unused for damage. Scroll Rack allows you to setup the top of your library to perfectly match the amount of Yuriko triggers you have on a given turn and helps dig for more big spells to hit with. You can activate it in response to the damage trigger on the stack as well. So you can use the same card to damage the table twice in one turn, and use the same card for damage multiple turns. There are 3 other cards in the deck that act as backup copies of this card as well and I'll put them in order of best to worst.
While Lim-Dul's Vault may not allow you to put cards from your hand back into the deck, it makes up for this weakness by allowing you to dig through your whole deck to find the best grouping of 5 cards, and then order them however you like for damage triggers. You can look at sets of 5 cards for 1 life each and the first one is free. Theoretically you could look through 90 cards in your deck (18 sets of 5 cards) for 17 life, finding the best combo of high CMC cards to kill your opponents. Brainstorm is the next backup card for Scroll Rack. Unlike Lim-Dul's Vault it doesn't let you dig anywhere near as deep, but it does let you put cards from your hand back onto the top of your library. It is the only other effect in the deck that can do that. That alone puts it a spot above Sensei's Divining top. The top is still great for the deck. You can stack the top 3 cards which has dimminishing returns the more triggers you have, but the real strength involves changing these cards on the fly. Maybe you setup the top of your deck for 3 Yuriko triggers but one or two of your Ninja's die before combat and now you will only get one trigger. Now you can rearange the cards on top on the fly to match whats happening in the game. Good cheap effective topdeck manipulation. But the weakest of Scroll Racks backups because it doesn't put cards from hand into library, and it doesn't dig deep enough to beat Lim-Dul's Vault's value.
This is definitely an all-in card. You really only want to cast this when you have a Counterspell in hand to protect it. The tempo loss from having to discard cards even if the spell is countered can be hard to come back from. But if it can be protected, it's the easiest way to win in one turn. Ideally you wait for a turn when you have atleast 3-4 Yuriko triggers and cast it as a response to the first trigger. Once you successfully cast this card you simply gather the 3-4 biggest spells in the deck, put them on top and win that turn. You can put Temporal Trespass, Deep-Sea Kraken, Commit // Memory, and Expropriate on the top of your library and hit the table for 40 in one turn. This is under the assumption that no one has taken any damage all game. You may be able to get away with fewer Yuriko triggers, less card discard, or tutoring for lower CMC spells if life totals are low across the table. There are also a few replacement/backup cards for Insidious Dreams as well. In order of best to worst:
We already went over Lim-Dul's Vault as a backup for Scroll Rack, but its also a backup for Insidious Dreams. It allows us to really stack the triggers deep to try and get the most damage out of a single turn. You can't mix and match like Insidious Dreams but you can find the highest hitting pocket of 5 cards for hopefully lethal. Spire Owl is a surprisingly good card for this strategy. Being able to have this effect on a stick is great. It doubles as an 'unblockable' creature to ninjutsu with. Your ninjas can bounce spire owl to your hand and you can reuse it right before a Yuriko trigger. It does get worse the more ninjas you hit with as you may be flipping 4 cards over no matter what so rearranging them wont matter, but its good in the early game for single or double triggers. And the late game if you havn't beenable to develop your board due to spot removal, board wipes or sac effects. Vampiric tutor is next because it allows you to grab any card in your deck and put it on top of your library. Very good if you just need that last little bit of damage to kill someone, you can instantly find the damage and put it on top of your libary. You will cast this tutor during your main phase pretty often. Same for Mystic Tutor. It hits less targets than Vampiric tutor, but has the same effect. These tutors can also be copies of Insidious Dreams itself, but I am ranking them in order as individual cards to stack damage.
