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 is a new phase of the Duel, Quantum Phase, and turn count becomes a fully cemented mechanic. Lastly, they debut a new effect type, Quantum Effects.
Quantum Monsters are similar to other Monster card types. They use Ranks like Xyz Monsters. These cards have a red layout with clock imagery in the background. To compensate for their Quantum Conditions, which can be up to 2 lines long (if not more), their effect boxes are taller (roughly the size of Pendulums if the Pendulum Effect and Monster Effect boxes were combined) with Pendulum Monster's transparency at the top where the box and artwork overlap. Their set number is in the same spot as Pendulums because of this.
As stated earlier, Quantum Monsters' "material line" determines the Condition required for a Quantum Monster to be Summoned in the Quantum Phase. 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 normally (this is based on the Player's individual turn count). Quantum monsters often have effects that take place in the Quantum Phase or require a certain turn count to be reached. Quantum Monsters are unique in that they do not require using Materials (for the most part).
Quantum Summoning is simple and occurs during the Quantum Phase. It can be done in one of two ways, "standard" summoning and Skip summoning. For standard Quantum Summoning, reveal a Quantum Monster from your Extra Deck whose Conditions can be fulfilled (called the Condition Fulfillment Step). Then, compare your monster's Rank to your Turn Count (Rank to Turn Count Comparison Step). If your monster's Rank is less than or equal to your own Turn Count, Quantum Summon that revealed monster to your field in any available Monster Zone, even the Extra Monster Zone. Regardless of the variation, you can perform Quantum Summons as much as desired in the Quantum Phase as long as Conditions and Rank are obeyed. Most Quantum monsters have hard OPT restrictions in their Conditions, to prevent excessive swarming.
Quantum Skip Summoning
Skip Summoning is a variant where you can Tribute only Quantum Monsters whose total combine Rank equals or exceeds the Rank of the Quantum Monster you want to summon during Rank to Turn Count Comparison Step. Like Rituals you cannot Tribute more than you need and you still have to fulfill the Condition. For balancing purposes, the Tributes' Ranks must also be less than the Quantum Monster's Rank, unless a card effect says otherwise. Quantum Skip is not an "official" PSCT term and card text instead uses the term "If this card is Quantum Summoned by Tributing Quantum Monsters" instead.
A unique phase taken in between the Standby Phase and Main Phase 1. Quantum Phase must be conducted and cannot be skipped, but you can choose to simply move on if you refuse to do anything with this Phase. More Quantum Phases can be provided via card effects. Battle Phases can take place in the Quantum Phase with card effects, where the standard rules for Quantum Phase are still applied, with the addition that only specified monsters can attack in those Battle Phases.
A new effect subtype that can only be used in the Quantum Phase, they all mention the Quantum Phase in either their conditions or in the actual effects. Any cards with effects can have Quantum Effects. Of course, Quantum Monsters will be the first to debut this effect type and will have them the most often.
Quantum Effects are subject to Spell Speed like all other effects, but unique to them, they have different Spell Speeds from non-Quantum Effects. Any non-(Quick Effect): Quantum Effects are Spell Speed 1.5, (Quick Effect) & Quick-like Quantum Effects are Spell Speed 2.5, and the Quantum Effects of Counter Traps are Spell Speed 3.5. Due to the nature of the Quantum Phase, there are no Quantum Continuous Effects.
Like all other effects, Quantum Effects can be negated and are not able to affect cards that cannot be responded to nor affect cards with effect immunity.
Quantum Split Summon
Another variant of Quantum Summon. Quantum Split Summon allows the Summon of 2 Quantum Monsters with different names at the same time.
Quantum Split pairs have one member say in their Conditions "Cannot be Quantum Summoned in the Quantum Phase, except by the effect of (Split Partner). For the rest of this turn you cannot Quantum Summon". Meanwhile, the other member has the phrase "You must have not Quantum Summoned to Quantum Summon this card" in their Condition AND the effect "When this card is Quantum Summoned, Quantum Summon 1 (Spilt Partner) (from your Extra Deck). (This is not optional)". You must be able to Summon both monsters in order to Quantum Split Summon.
Note while they can be Summoned via Quantum Skip methods, the Summon is still labelled as Quantum Split Summon regardless of the method.
Quantum Summon Chants
When a player uses their Quantum Phase for anything, they shout "Quantum Phase Initiate!".
When revealing a Quantum Monster they list that monster's conditions with the phrase "If I (Quantum Conditions), I can open the gate of time!" as they place the Quantum Monster from their Extra Deck to the field, they say "(Unique phrase)! Quantum Summon! Rank (number)! (Quantum Monster name)!"
When Quantum Skip Summoning, the phrase is altered. Now, the player instead says the Quantum Monsters they will Tribute with the phrase "With (List of Quantum Monsters from lowest Rank to highest and their Ranks, with the Rank mentioned first), I force open the gate of time!" the rest of the chant is the same sans the statement of Quantum Skip Summon, "(Unique phrase)! Quantum Skip Summon! Rank (number)! (Quantum Monster name)!"
For Spilt Summoning, the chant is either of the following
Normal Split: "If I (Quantum Conditions) I can open the gate of time to two separate futures! Quantum Split Summon! (Unique phase for the first monster)! (Quantum Monster 1)! And! (Unique phase for the second monster)! (Quantum Monster 2)!"
Skip Split: "With (Quantum Monsters that will be Tributed (State first, name second, lowest State to highest)), I force open the gate of time to two separate futures! Quantum Split Summon! (Unique phase for the first monster)! (Quantum Monster 1)! And! (Unique phase for the second monster)! (Quantum Monster 2)!"
Visuals for Summon
Quantum Summon invokes time, clock, and gate imagery. When the Quantum Phase is initiated, the area around the duelists (and spectators) freeze in place as everything becomes grayscale. This lasts until the Quantum Phase is ended. When Quantum Summoning, a clock then appears behind the Duelist out of nowhere. 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 yellowish gold: FIRE is red, WATER is blue, WIND is green, EARTH is bronze, LIGHT is white, DARK is purple, DREAM is pink, TIME is silver and DIVINE is metallic gold. The numbers on the clock (up to the monster's Rank) light up (if it is 13, the number 13 appears in the center).
What becomes of the clock "gate" afterwards is different based on the variation. The normal version has the gate split in half and release the monster(s). In the Skip version, it absorbs the Tributed Quantum monsters before breaking apart as the monster(s) come out.
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 source. It is the dream of many to attain this potential state. 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 the plane 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.
- This mechanic is inspired by the concept of "Quest Monsters" made by Yugioh Everything and mentioned in one of his videos. He describes them as monsters summoned from the Extra Deck when certain conditions are met during the Duel.
- This mechanic is also similar to Cardfight Vanguard!'s Stride mechanic, both being time-related cards brought to the field from a separate deck from the Main Deck during a unique phase made specifically for them and are red.
- The Split variant is based on Legion from the same game, bringing 2 paired monsters to the board at the same time.
- While not an inspiration, a YouTuber by the name of Champion Darkblaze! made his own summon mechanic, named Quantum Summon.