DISCLAIMER: This support is to help bring this archetype up to the level of the current Meta of 2019/20. If designing this archetype from scratch I would do so differently to Konami, but building on their bad foundation, this is how I would look to improve things without outright creating one of the most broken cards created in Spellbook of Judgment.
Her first effect is to give Spellbook/Prophecy a way of consistently getting another monster on the field for Crowley and help out with board presence in general. She supports all variants of the Prophecy archetype, including High Priestess (Justice), World (Temperance) and Reaper (Fool) as well as some XYZ variants that might use Hermit and maybe even Amores. She summons only Level 3 "Prophecy" monsters to avoid becoming a splashable engine with Spellbook Magician of Prophecy, though her restriction of summoning only Spellcaster monsters also helps with that.
Her second effect simply does what her name and attribute implies (she's the Master of "Blue Boy") - adding a Spellbook from Deck but also from GY as well, meaning you can grab back a destroyed Spellbook Grand Tower, Spellbook of Eternity etc which means having to play less copies of those cards and therefore bricking less.
Prophecy supports Spellbooks, Spellbooks support Spellcasters. Therefore, Spellbook spells can't reference the Prophecy archetype in their text. Konami's crappy translation of "Magicial" into "Prophecy" but "Magical book" into "Spellbook" is annoying. Nonetheless, this card functions as generic Spellcaster Ritual support. Banishing Spellbooks is a way to help alleviate some of the cost of Ritual Summoning, while the second effect is to help this deck with going second which is a struggle for Spellbooks/Prophecy. It requires that your opponent controls more monsters and you have 3 Spellbooks with different names in the GY, but in return it summons a Level 5 or higher Spellcaster to help counter the opponent's field, albeit with their effects negated. It helps make Spellbooks like Master and Power more consistent since they require a Spellcaster on the field.
Simply a much improved Spellbook of Wisdom but for monster effects. The only thing I'd think about changing is the first effect's ability to protect cards in the GY - I may leave that as a vulnerability on purpose, but then the card only protects one single card unlike certain cards like Miscellaneousaurus so it's probably fine as is.
I designed this card to be a decent option going first but a powerful option for the deck when going second. The first effect sends a Spellbook to the GY which, going second, means being able to send Evocation or Spirits to help create field presence or protect yourself as you try to play against today's ridiculous boards. The second effect only corrects a card in the hand which is still -1 overall and it has a fair activation requirement, but against a big field it can provide good removal. As a downside, if the player is unable to get rid of this card then they are locked into playing no Spells other than Spellbook spells while it's face-up. Not much of a hindrance to Spellbooks/Prophecy, the deck that needs to this kind of card going second, but it is for a deck like Pendulums if they tried to splash this in.
I like creating a splashable "traitor" card in archetypes that help counter their own deck as a way to keep that deck in check if it ever were to become dominant, e.g. like Abyss Dweller. The original Prophecy Destroyer was too hit or miss for my liking. Sure, it enabled some OTKs since it wasn't once per turn, but it was such a dead draw that many decks just didn't run it. Still, I designed this card to still give use to the original which I'll mention later.
Firstly, it's unable to be returned from the field or GY to the hand. This is primarily to prevent looping the card, but it also serves as a bit of protection against cards like compulsory evacuation device though your opponent is unlikely to want to return this card to your hand anyway. Secondly, it banishes a searched card until the opponent's EP. This helps slow decks down or outright end their turn if you manage to snipe a key card, but to balance this the opponent takes no battle damage during your next Battle Phase. This is to ensure that the opponent does get the opportunity to play the card they searched, but the player gets a chance to play between that. Last, it's final effect is a hard once per turn on the original Prophecy Destroyer. This is to disable some OTKs, give this card a benefit when played within its own archetype (Dweller gains atk when a water is used as material) and also to keep the original Prophecy Destroyer an option for those players who might want to tech one in for the OTK potential.
Also, the art (credit to whoever made it) of Prophecy Destroyer dropping Spellbook Magician's Spellbook of Secrets after snatching it just matches so perfectly with it being an anti-search card - https://youtu.be/RHlC9DJLKb8?t=257
Thanks for reading and feedback is welcome. I have other support that I'd like to post as well but the camera in DB isn't working for custom cards atm so I'll have to post them another time
Also, if you'd like to have a play around with these cards then let me know and I'll make them public on DB.
