This is my version of Bystial Centur-Ion. It might not be a Tier 1 Deck, but it's solid, with a good grind game, and pretty fun to play. Reminds me a bit of my old Punk Bystial deck, minus the crazy Chaos Ruler mills of course.
The gameplan is simple, during your turn, you aim to make a LV 12 Centur-Ion Synchro (either Centur-Ion Auxila or Centur-Ion Legatia), and set up Centur-Ion Primera and Centur-Ion Trudea in the backrow. This setup allows you to summon Crimson Dragon on your opponent's turn, to go into a powerful monster like Cosmic Blazar Dragon, which most decks will struggle to play against. Bystials provide extra bodies for additional Synchro Summons (possibly LV 10 like Baronne de Fleur or Bystial Dis Pater), draws using Branded Regained and are also very solid disruption, not only against the GY (Voiceless, Yubel, Tearlaments, etc.) but also on the field (don't sleep on Bystial Baldrake).
It's 41 cards (you can cut something to get to 40 if you really want to), consistency doesn't feel like an issue with 12 Centur-Ion starters (14 counting Bonfire). However, only having 1 in-archetype Tuner makes the deck somewhat fragile against removal, it really hurts if Centur-Ion Primera is removed from the field, and that makes it tough to go 2nd. To try and remedy that, you play a decent amount of handtraps, plus some extra Tuner monsters that can be Special Summoned, like Assault Synchron and Agnimal Candle (it's like Poplar if you get it with Bonfire, not so good if you draw it). I'm sure there are other options (some Resonators maybe?) and you can play around with them, but these feel fine for me. Also, at first I was also playing Centur-Ion Bonds, it's a decent card but it felt a bit bricky to have 3 one-of Centur-Ion spell/traps, so I cut Bonds for another copy of Effect Veiler.
On the Extra Deck, you really need at least 1 copy of Centur-Ion Legatia and Centur-Ion Auxila (but you can play more, I like 2 Legatia), Crimson Dragon and Cosmic Blazar Dragon. Baronne de Fleur and Chaos Angel come in handy as your LV 10 options. Everything else is somewhat flexible. I feel like Red Supernova Dragon would be useful as an alternative target for Crimson Dragon, but I don't have it (it is UR) so I was playing Stardust Sifr Divine Dragon as a budget option. You could even play a 2nd copy of Blazar if you have it, but 1 is usually enough. Besides that, play any LV 12 and LV 8 Synchros that you like.
I was playing an XYZ monster (could be useful in some scenario where you don't have access to tuners), Number 90: Galaxy-Eyes Photon Lord, as well as Super Starslayer TY-PHON - Sky Crisis and Divine Arsenal AA-ZEUS - Sky Thunder (both of which can, funnily enough, be hard-summoned in this deck, should the need arise). Dingirsu, the Orcust of the Evening Star could also be useful, but I also don't have it yet. You could also consider a link package, consisting of Artemis, the Magistus Moon Maiden (since Primera is a spellcaster), S:P Little Knight and possibly I:P Masquerena (combine I:P with Bystials for maximum efficacy).
Check out the video to see the deck in action. I hope you enjoyed it, feel free to share your thoughts!
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