Hello, this is the first deck I'm submitting ever, so I'm gonna try and explain what the idea behind its strategy is.
Hieratics:
-Monster gate is basically a hieratics card, using this is a bit risky if you run many handtraps but it gives you so much adavntage by using a hieratic as a targer it's a no brainer to use, then, you want to prey not to get an ash on field with its effect
-Creation is great to use to cheese out atum a second time, since you can use one atum to go into gaia, then overlay the other atum on top of gaia.
-Convocation is hieratic's rota, with it you're mostly gonna add su, and if you're going second you might wanna consider tefnuit
-Tefnuit is hieratic's cyber dragon, it's great going second, but if you are first you are mostly gonna use him by discarding it some way
-Eset is just ok, if you have him first you might wanna summon it or just using it as discard fodder, main use of this card is to summon it via Atum
-Su is extremely great, you wanna ss him by tributing spheres, however you manage to get them onto the field (more on this later), and you always wanna have one or more in hand, he's used to summon atum 100% of the times
-Spheres is the first extra deck monster you wanna summon, I suggest summoning it using collapserpent and wyverbuster or seyfert: you use one of the babies to summon Striker, and add the other baby to hand to summon itself by banishing the other baby, and then use them both to go on spheres. After that, tribute the spheres to summon su from hand, and maybe another su of tefnuit from deck. Remember that sphere's effect only activates once, so it's no use getting him back on the field with darkness metal dragon
-Atum is great: the first time you are gonna use its effect for an easy darkness metal dragon, which will allow you to ss from grave su, then you either link atum and dmd into romulus, or if you have creation you want to summon gaia to use creation and rank up into atum again. Second time you are gonna use its effect is gonna be to summon samsara dragon, then you get samsara in grave and use its eff to summon a lv6 by using the other su as tribute, this way you have two other lv6 to go on Beyond, another Atum, or Bounzer.
Byssted
The Bystial Lubellion
-Lubellion is great, it's a Rota for byssted and can special summon himself from grave by tributing a dark dragon, which is of course going to be either a byssted or the labradorite, and when he hits the field, you are going to activate Branded beast, which we'll talk about in just a second
Bystial Saronir
-Saronir is going to be a key component to the byssted end board, as all level 6 byssted you can summon him by banishing 1 light or darkness from either graveyard, if it's gonna be yours, I suggest striker dragon or maybe an atum, but anything is fine, then, you want saronir to go to grave, either by linking him away, or by summoning lubellion from grave, or by going into autm. Once he hits the field, you wanna send Branded regained (formally known as rebranded (which in my opinion sounded a lot better)). Having branded regained on grave is gonna be extremely great, you'll see why in just a moment.
Bystial Magnamhut
-Magnamhut is great, if you can summon him, go for it, even during your opponent's turn, as he's gonna add you a dragon from deck or gy, this is extremely great to have as an effect as it may help you gain extra deck monsters for your next turn, or other byssteds to be used with the spell and traps
Bystial Druiswurm
-Druiswurm is also great, you're going to summon him during your opponents turn mostly and you want to get him off of the field to pop 1 of your opponent's monsters, which is a really valuable effect
Branded Beast
-Beast is the trap card, you wanna place this one on your field via Lubellion's effect, it's gonna be a form of removal via tribute, which is gonna trigger your druiswurm or hieratics, but also, it allows you to place branded regained on the field from grave, which is great
Branded Regained
-Rebraned is the spell one, this has two effects that can be activated during your opponent's turn to give you advantage: first, if a monster is banished, it lets you add that monster to the deck and draw 1, basically another chaos space, and this effect is going to be activated whenever you summon a byssted during your opponent's turn, so mainly when you summon druiswurm. The second effect is going to trigger when you opponent summons, this is going to let you summon one byssted from grave, either druiswurm or magnamuth to setup a card for your next turn
Dragonlink package
Starliege Seyfert
-Seyfert is really great, you wanna use it to search for a collapserpent or for a Saronir, with collapserpent you want to go into spheres to be tributed using su, and with saronir you want to setup the end byssted board, may have other uses but these ones are the main ones in my opinion.
Black Dragon Collapserpent
White Dragon Wyverburster
-The babies are extremely great at giving you spheres or romulus, in case you don't know how: summon one baby, link it away into striker, add the other one to you hand, banish the baby to summon the second one, link the second and striker into your link2 dragons. These bad boys are going to make your combo way easier.
Chaos Space
-Chaos space is basically a spell version of seyfert, it's great + it lets you draw one
Dragon Ravine
-Ravine is extremely good with this deck: you wanna use it to send samsara dragon and the guardragon one, or to send lubellion, I suggest samsara just because he's gonna be used to allow you to go into atum a second time with ease
Dragunity Knight - Romulus
-Romulus: add ravine and maybe summon 1 from hand if you're really feeling it
Striker Dragon
-Striker is just gonna be fodder to go into your link2
Guardragon Pisty
-This one is a bit finnicky to use in this deck, but it can work: summon him in left zone, and then summon triple burst dragon in the extra zone afterwards, not the other way around, please. You can then use the effect to summon whatever you want to extend your plays, maybe an apollousa could be an idea idk I never know what's the right call with this situation so you might wanna try some stuff by yourself
Triple Burst Dragon
-Trip is going to let you use pisty if you're feeling like it, summon pisty before this one please
Lv1 Dragons + labradorite
Samsara Dragon
-samsara is cute and really helpful, you wanna send him to grave via ravine, then trigger its effect to summon a level 6 from grave by tributing a hieratic on field, if you remember the combo is atum>dmd>su from grave> romulus with atum and dmd, so you're always gonna end up with a su or tefnuit to use as a tribute, and being tributed is gonna let you summon labradorite to go into atum a second time
World Chalice Guardragon
-Guardragon is also very cute, and also likes to be on grave, you can send him via ravine (BUT remember that samsara has the priority), or you wanna summon him with the second atum's effect specifically, then you link him away and use its effect to bring labradorite on field once again, an extra body is always great
Labradorite Dragon
-Lab you wanna use to summon the 2nd atum, or if you wanna hurt yourself and use the tzolkin variant of the deck you can summon him, otherwise, you summon him via guardragon to go into utopia or bounzer
Other extra deck
I:P Masquerena
-Masq is gonna be used to summon knightmare or apollousa if you're playing her
Photon Strike Bounzer
-Bounzer is a monster negate and a decent attacker, but remember that he negates monsters that are already on the field, go into this one at the end of your combo using labradorite and another lv6 but remember that he's not gonna be super useful
Number 39: Utopia Beyond
-If you're going to attack for critical this one is decent, never use him if you go first though
Gaia Dragon, the Thunder Charger
-Gaia is only useful if you have creation in hand, otherwise, consider using him as fodder for prosperity
Ultimaya Tzolkin + Void Ogre Dragon + Crystal Wing Synchro Dragon + Lost Wind
ultimaya is pretty bad 90% of the time, but if you like suffering you can add him to your ed (not sure what to remove tho) and you wanna summon the two dragons, if you feel really cool you can set lost wind from grave during your opponent's turn.
Side deck+ cards to consider
Constellar Ptolemy M7
-Ptolemy is one I forgot to add this one but is sometimes better than the other rank 6
Card Advance
This one lets you tribute summon one extra time and also lets you setup your next draw, unfortunately you're almost never going to set the next card because you often wanna tribute hieratics that usually summon stuff from deck
Dragunity Arma Gram
-Arma gram is a strong dude and a negate, you might wanna use him when going second by summoning him from grave
Amorphage Sloth + Zerozerock
-If you manage to trigger sphere's during your opponent's turn this one is a neat floodgate but unfortunately is always gonna have 0 atk/def, so you might wanna add zerozerock idk your choice anyways this one is gonna be at the very least an annoyance to remove since your opponent is most likely gonna waste the battle phase
That's all goodye