Yu-Gi-Oh! Quantum monsters

Monsters that break time and space!

Quantum Monster is a new Monster card type that starts the Duel in the Extra Deck, sharing the same properties as other Extra Deck card types. With their inclusion, turn count becomes a fully cemented mechanic.

Design
Quantum Monsters are similar to other Monster card types in frame design. They use Ranks like Xyz Monsters. These cards have a red layout with clock imagery in the background. They are similar to Pendulum Monsters where they have 2 effect boxes, one for their Quantum Conditions, and one for their actual effect. Their set number is in the same spot as Pendulums because of this.

Features
As stated earlier, Quantum Monsters' "material line" is the Quantum Condition Box. This determines the Condition required for a Quantum Monster to be Quantum Summoned. For most Quantum monsters, it is worded "Only once per turn, Quantum Summon (monster name) if (condition)". The Rank determines the first turn they can be Quantum Summoned. Quantum monsters often have effects that require a certain turn count to be reached or have time related effects in general. Quantum Monsters are unique in that they do not require using monster materials.

Quantum Summoning
Quantum Summoning is simple and occurs during either Main Phase. For standard Quantum Summoning, do the following: fulfill the conditions (which can be anything from cards you control; to your LP count; to the number of cards in your hand, deck, GY or that are banished; anything within Yu-Gi-Oh's mechanics really), have the monster's Rank be less than or equal to your turn count, reveal the monster and Special Summon it to any available Monster Zone, even the Extra Monster Zone.

You can Summon any number of Quantum Monsters in a turn, as long as their total combined ranks are under or equal to your current turn count (This is known as your Quantum Summon Limit).

Turn Count mechanics
Each player starts the Duel at Turn Count 0. Turn Count increases during each player's Draw Phase. The maximum turn count number is 12 and will stay that way for the rest of the game after being reached. In addition to Quantum Monsters, some card effects (Quantum Monsters or not) rely on the turn count number.

Quick Quantum Summon
Quick Quantum Summon is an unofficial term referring to the process of Quantum Summoning during the opponent's Main Phases, using their Turn count instead of yours. Quantum monsters that can be Summoned with this process have the statement "During your opponent's turn, you can Quantum Summon..." in their condition. You can Quick Quantum Summon as much as possible, as long as you obey their conditions (which you have to fulfill, not your opponent, unless otherwise stated) and the Quantum Summon Limit (again using your opponent's turn as the basis). Quick Quantum Summoning is especially advantageous for the 2nd player, as they can summon Quantum Monsters of slightly higher Ranks faster than they would normally.

Quantum Split Summon
Another variant of Quantum Summon. Quantum Split Summon allows the Summon of 2 (or maybe more) Quantum Monsters with different names at the same time. Quantum Split pairs have one or more members say in their Conditions "Cannot be Quantum Summoned, except by the effect of (Split Leader)". Meanwhile, another member has the effect "When this card is Quantum Summoned, Quantum Summon 1 (Spilt Partner(s)) (from your Extra Deck). (This is not optional)".

You must be able to Summon all monsters who are part of the Split group in order to Quantum Split Summon. Your opponent cannot interrupt the process of Quantum Split Summon until the last member(s) is Summoned. While you do summon multiple Quantum Monsters, only the first member counts towards your Quantum Summon limit in a turn, effectively making the other member(s) free.

Quantum Monster Samples
Non-effect Quantum Monster
Metal Star Dragon
Rank 3/LIGHT/Dragon/Quantum
2500ATK/0DEF
QC: Once once per turn, you can Quantum Summon "Metal Star Dragon" while your opponent controls 3 ore more monsters than you.

Effect Quantum Monster
Paradoxical Machine MAG-iX
Rank 6/EARTH/Machine/Quantum/Effect
3000ATK/1800DEF
QC: Once per turn, you can Quantum Summon "Paradoxical Machine MAG-iX" by having 10 or more Machine monsters in your GY, and no "Paradoxical Machine MAG-iX" on your field.
Effect: Unaffected by your opponent's Spell effects. Cannot be destroyed by battle or card effects of monsters, except Earth monsters. If this card is in your GY during the start of your Main Phase, and you do not control "Paradoxical Machine MAG-iX": You can Special Summon this card from your GY.

Effect Quick Quantum Monster
Master of the Material World
Rank 4/DARK/Spellcaster/Quantum/Effect
0ATK/0DEF
QC: Once per turn, during your opponent's turn, you can Quantum Summon "Master of the Material World" by having 4000 LP less than your opponent.
Effect: For the rest of this turn: your opponent cannot activate card effects, except Traps, and all of their monster's ATK/DEF become their original ATK/DEF. Send this card to the GY during your opponent's End Phase.

Quantum Summon Chants
When revealing a Quantum Monster a player lists that monster's conditions with the phrase "If I (Quantum Conditions), and the turn is X or lower, I can open the gate of time!" as they place the Quantum Monster from their Extra Deck to the field, they say "Quantum Summon!"
When Quick Quantum Summoning, the phrase is slightly altered. "If I (Quantum Conditions) and the turn is X or lower, I can break the gate of time! Quick Quantum Summon!"
For Spilt Summoning, the chant is either of the following:
Normal Split: "If I (Quantum Conditions) and the turn is X or lower, I can open the gate of time into multiple futures! Quantum Split Summon!
Quick Split: "If I (Quantum Conditions) and the turn is X or lower, I can break the gate of time into multiple futures! Fast Quantum Split Summon!

Visuals for Summon
Quantum Summon invokes time, clock, and gate imagery. When Quantum Summoning, a clock then appears behind the Duelist out of nowhere. When Fast Quantum Summoning, the clock appears behind the opponent instead of the Summoning player. Each of the clock's digits is black.
The color of the clock is based on the Attribute of the Quantum Monster, or in the case of Quantum Split Summoning, its white with a rainbow gradient regardless of the attributes of the components: FIRE is red-ish orange, WATER is blue, WIND is green, EARTH is bronze, LIGHT is yellowish gold and DARK is light purple. Quantum Split Summoning also adds another distinction in that there are multiple connected clocks (in an infinity symbol with a pair and a triangular shape with a trio). The numbers on the clock (up to the monster's Rank) light up. Afterwards, what becomes of the clock "gate" afterwards is based on the variation. The normal version has the gate split in half and release the monster(s). In the Fast variant, it instead breaks apart as the monster(s) come out.

Lore
Quantum Monsters are said to represent those who exist beyond the concept of time itself. Because of this, they can travel to any and all time periods and timelines, manipulate the flow of time, and even use time as an energy resource. It is the dream of many to attain this potential state of existence. Many theories exist as to how one can become a Quantum Monster: from obtaining a lot of energy, to perfecting one's body, to attaining spiritual enlightenment, to mastering dimensional travel to reach planes beyond time. However, some people think Quantum Monsters are just a myth, and do not actually exist. Others think Quantum Monsters can exist, but not in the current time period, only after the fabled "Quantum Phase" is reached, presumably in the far future.