Fast mana is broken in Modern, so what sense does it make to run it in a deck that isn’t “broken” at all?
Desperate Ritual and Pyretic Ritual are longtime Modern staples. These are the enablers that make Storm work, and when coupled with Goblin Electromancer and Baral, they can proxy as Dark Rituals to take over the game. You’re not using them to generate storm count, and you’re not even using them to cast expensive cards. You have 8 of these red Rituals that accelerate you by a single mana to go with 4 Simian Spirit Guides, and yet there are very few cards in this deck that even cost more than 3 mana! Instead, you’re just looking to turbo out some of your lock pieces, and you don’t mind having fewer cards in hand.
The main way to lock an opponent out is through Blood Moon and Magus of the Moon. There are plenty of decks in the format with few answers to either, but when an opponent knows you’re on this Prison Red strategy, they’ll also know to use their fetchlands to find basics to make sure they can still cast their spells. Not so fast against this deck. With Spirit Guides and Rituals, you’re capable of playing a turn-1 Blood Moon! If you’re on the play, even if they keep fetchlands, they may never have a chance. They might also lead on a tapped land without realizing you’re capable of playing Blood Moon before turn 3 so you can fully punish them.
You’re also playing the full playset of Chalice of the Void. This can lock out decks that lean too hard on 1-drops, and shutting down 0s can even come in handy against Affinity or decks with suspend cards like Lotus Bloom or Living End. With all of the Rituals, you’re capable of shutting off even 2s early in the game.
The key to keeping your opponent from beating you comes from Ensnaring Bridge. The same tool that makes Lantern decks so powerful works well here as the card disadvantage from playing Ritual effects just means that your Bridges are active earlier. With Moons helping to shut off their spells and Bridges to lock out their creatures, you’re putting your opponents in a spot where they can no longer win.
Once they can’t win, winning becomes academic. One of the best ways to accomplish this is with planeswalkers as they can help control the board and still win the game through your Ensnaring Bridge. Chandra, Torch of Defiance is even more powerful when you’re Ritualing her out on turn 2 or 3. Kill a creature, add more mana, get card advantage, and eventually win the game. Koth of the Hammer is also excellent in your Mono-Red deck as a quick clock that can ultimate fast to shoot down opposing threats and win the game that way.
Token makers are also strong with a Bridge in play. Leave your card for the turn in your hand before you attack. Goblin Rabblemasters will win single-handedly in a hurry, and a threat that doesn’t die to Fatal Push. A turn-2 Rabble on the play can put the game out of reach even before W/U can cast their sweeper. Pia and Kiran Nalaar produce some flying threats and the ability to burn your opponent out (or just sacrifice your Bridges to attack for lethal).
Walking Ballista gives you a late-game mana sink and an early way to interact with a creature rush. This is a nice removal spell that pairs with your Abrades and Slagstorms to keep creatures under control.
This deck goes all out to set up its lock early by not only relying on Simian Spirit Guides and Rituals, but you have 3 Gemstone Caverns to “steal” the play when you’re on the draw and still set up your Moons when they only have one land in play! With so much fast mana to turbo out these lock pieces, Red Prison is a nightmare to face and a blast to play.