Synchro Summon was the first new summoning method introduced after the adoption of the Master Rule in Yu-Gi-Oh! In terms of the story and lore, it marked the start of an entirely new era in Duel Monsters.

The summoning rule is actually very simple—just basic addition and subtraction within 12.

As mentioned before, many monsters have untapped potential. Some can combine their own level with that of their partners, a power called "tuning." Monsters with this ability are called "Tuners."

A Synchro Summon uses one Tuner plus any number of non-Tuners. Add up all their levels, and if the total matches the level of the Synchro Monster you want to summon, you can perform a Synchro Summon.

Just like Paradox was demonstrating now.

Level 2 Tuner "Malefic Parallel Gear" and Level 8 non-Tuner "Malefic Stardust Dragon"—2 + 8 = 10. So the corresponding Synchro Monster must be Level 10.

Parallel Gear’s body disassembled, turning into two green rings revolving around Malefic Stardust Dragon. Stardust’s body became transparent, its energy extracted and turned into eight glowing stars.

The stars aligned, a pillar of light pierced the heavens, forming a stellar pathway to the ground. The dark dragon landed with a roar that shook the earth.

Malefic Paradox Dragon, Synchro Summon!

[Malefic Paradox Dragon, ATK 4000]

Everyone in the research lab, including Mokuba, was stunned.

What the heck? What just happened to those two monsters? How did they become this dragon? What just happened?

"This is a duel that transcends time—a summoning method of the future."

Paradox sneered, but then his expression turned somber.

"Yes... the summoning method that destroyed the world."

In Paradox’s future, dueling had literally destroyed the world. This timeline was ruined by dueling—specifically, by the advent of Synchro Summoning.

When Synchro Summoning appeared, it changed the world’s entire structure. The method was bound to a revolutionary new energy engine called "Ener-D."

Ener-D was called a perpetual-motion machine, but was actually a pseudo-perpetual machine. Its energy was inexhaustible, but it needed the passion of duelists to fuel it—duelists had to keep Synchro Summoning to maintain its operation.

But extremes beget disaster. Ener-D ushered in a new age of infinite energy, but the Earth was ultimately destroyed when Ener-D went out of control.

This was why Paradox and a few survivors traveled through time to rewrite history. Paradox believed that if Duel Monsters never reawakened in the modern era, Ener-D would never appear, and humanity’s technology would take a different path. It wouldn’t be as glorious as the perpetual-motion era, but at least it wouldn’t end in destruction.

Paradox glanced at the unfazed Kira, frowning.

He thought seeing "Synchro Summon," something from the future, would shock his opponent. But Kira only calmly observed the newly summoned Paradox Dragon.

Then Kira suddenly spoke: "This era shouldn’t be able to use Synchro Summons... I see. Your duel disk, and the time-traveling device you used.

Those contain miniature perpetual-motion engines, don’t they? Those engines are constantly releasing ’Planetary Particle,’ so Synchro Summoning is possible only in this stardust-particle-filled duel zone."

Paradox: "!!?"

The future duelist’s eyes nearly popped out of his head as he stared at Kira.

That’s right—the key to Synchro Summoning is the newly discovered "Planetary Particle." The perpetual-motion engine produces them, and their presence is necessary for Synchro Summoning.

Kira had tried to develop Synchro Summoning in his own era, but gave up because there were no Planetary Particle. Even if he could design Synchro Monsters, there was no point without the hardware.

This was common sense for a future duelist from the 5DS era. But Paradox was shocked—how could this duelist from the past know?

He stared at Kira for a while, then asked, "You’re not from this era. Who are you?"

"Who knows?" Kira smiled. "I don’t understand what you’re talking about."

Paradox snorted, but was now even more wary of him.

Not only was he strong, but he seemed to have secrets.

He definitely cannot be allowed to live!

"Malefic Paradox Dragon’s effect!" Paradox declared. "When this card is Synchro Summoned, select one Synchro Monster in either graveyard—ignore its summoning conditions and revive it to your field!" (Anime effect.)

Kira naturally had no Synchro Monsters in his graveyard, but Paradox had one—the one he just sent from his Extra Deck to the graveyard to summon Malefic Stardust Dragon.

Paradox raised his hand. A vortex opened over his graveyard, spiraling starlight shot up, and a silver dragon spread its wings, raining stars down.

"Fly! Stardust Dragon!"

[Stardust Dragon, ATK 2500]

The ace monster of Yusei Fudo, protagonist of 5DS—Stardust Dragon!

The original Paradox Dragon also had a stronger effect: all monsters on the opponent’s field lose ATK equal to the revived Synchro Monster’s ATK.

Now, Paradox Dragon revived Stardust Dragon, so theoretically all of Kira’s monsters would lose 2500 ATK.

But of course, "Skill Drain" also negated this effect.

"Battle!" Paradox roared. "I don’t care who you are or what secrets you have—disappear for the new world! Paradox Dragon, attack the weakened ’Archlord Kristya’!"

Endless energy gathered in Paradox Dragon’s mouth, condensing into black lightning, firing straight ahead!

"Then I activate my set card," Kira said, waving his hand. "Trap Card—’Malevolent Catastrophe’! When a monster declares an attack, destroy all monsters on the field!" (Anime effect.)

A trap used by Marik in Battle City, later changed in the card game to destroy Spells and Traps.

"A board-wiping effect, huh?"

Paradox laughed.

"But against Stardust’s power, it’s useless! Stardust Dragon’s effect activates!

Sanctuary of the Sacrificed!"

PS: My brain is not functioning. What the hell with this synchro summon? Summoning any monster card just base on total level? Damn...