Red Dragon Archfiend ft. Rokkets

The King's deck itself. Red Dragon Archfiends focus on Synchro Spamming through their sub-archetype "Resonators," which were also used by Jack in the anime, with non-Tuners and backrow to boot. This particular build utilizes the advantage that the "Rokket" cards provide. Rokket Tracer can serve as a Tuner or as a non-Tuner by destroying itself to Special Summon Rokket Recharger, whose effect itself can be helpful in the duel, and can serve as a smaller Tuner by destroying itself to Special Summon Rokket Synchron, which is also useful for extension and recovery. Rokket Tracer is also excellent for combo'ing with the Spells or useless Resonators, as you can destroy them to Special Summon Recharger and make an easy Level 8 Synchro.

The best end boards are always gained through the help of Crimson Resonator. Crimson Resonator is an insanely powerful card that Special Summons itself if you control no monsters, which saves your Normal Summon for an extender or just a Level 4 for the Synchro Summon of Red Rising Dragon. Red Rising Dragon is a very valuable part of the deck, as it is a Level 6 Synchro which is easy to make through a Level 2 Resonator and a level 4 non-Tuner like Wildwind. Red Rising Dragon's effect revives a Resonator from the Graveyard, most likely the one you used for its Synchro Summon, allowing you to immediately go for another Synchro Summon, usually for Scarlight Red Dragon Archfiend of Chaos Ruler, the Chaotic Magical Dragon.

Chaos Ruler is great because none of the good Synchros require specifically a Red Dragon Archfiend, instead requiring any DARK Dragon Synchro Monster, and Chaos Ruler can mill 5 upon Summon. This is an amazing effect because Synkron Resonator and Wandering King Wildwind are both DARKs you can add back from the effect, you can recycle dumped Resonators with Synkron or any dumped card with Burning Soul, and I would hate to fail to mention that milling Red Reign will allow you to add it right to your hand on your next Synchro Summon. Milling "The Great Soul" also gives you access to a negation of an opponent's monster effect that activates anywhere, and the fact that it's a Trap and banishes itself from the Graveyard as cost makes it even stronger, as most opponents would need to already have an omni-negate present on their field in order to negate it, and this strengthens your chains with Supernova, Red Reign, and Abyss disruptions.

When going first, provided that you didn't brick (which happens a lot, albeit less frequently with this build than with others), you should be able to make Red Rising Dragon, hopefully with a Crimson Resonator to revive. Then you can use Crimson Resonator to Special Summon a Synkron Resonator and a Creation Resonator from Deck, then you can use your three Tuners and your non-Tuner Synchro Monster to Synchro Summon the almighty Red Supernova Dragon. Even by himself, he can be a game-ender if the opponent doesn't have the resources to bait his effect out before making their main plays. However, it's usually possible to secure a Hot Red Dragon Archfiend Abyss alongside him for added security.

Alternatively, if you've drawn a hand that can make Red Supernova Dragon, and you've drawn Burning Soul, you can prevent your opponent from playing the game. Simply make Red Rising Dragon once more using Crimson Resonator and Special Summon your Synkron and Creation Resonators. Alternatively, if you have a copy of The Great Soul, or a Trap Trick to gain access to one, then all you need is the Crimson Resonator, or even just a Red Resonator. Now, instead of making Supernova, make Scarlight or Chaos Ruler. Chaos Ruler is usually preferred, since you can potentially score a DARK monster, Red Reign, or The Great Soul off of the mill. Set Burning Soul and maybe a Trap Card, then end your turn.

At the start of your opponent's Main Phase 1, activate Burning Soul. Add whatever card to your hand, then perform your Synchro Summon, tuning your Level 1 and 3 Resonators to your Level 8 DARK Dragon Synchro Monster to Synchro Summon the also almighty Hot Red Dragon Archfiend King of All Mouthfuls - ahem - King Calamity. Just like another monster with Calamity in its name (or rather the plural version), this monster makes it so your opponent cannot play the game by preventing them from activating cards or the effects of cards on their fields. On top of this, it's a Spell Speed 4 effect, meaning it cannot be responded to with any card of the game. Now all your opponent can do is Set a monster and maybe some backrow and pray to whatever deity they worship that you don't have a hand coherent enough to kill them next turn, which seems a little optimistic, given you added a card from your Graveyard to your hand, you're drawing another card, and you likely have a Wildwind and/or a Red Rising Dragon to activate for more advantage.

Of course, this list is not 100% perfect. Some ratios can be adjusted to fit how you'd like to play. I've experimented with things like Dawnwalker, Duskwalker, and the Assault Mode package for easy Synchros, adding more Chaos cards like Chaos Valkyrie which is an easy-to-summon Level 4 and a LIGHT for recurring Chaos Ruler, and much, much more. This is simply the easiest, most reliable version of the deck that I've made thus far. I hope this is helpful for your future duel-ruling endeavors, Kings.