Sarina didn't explain it, but Kira seemed to have a faint impression of that eerie "Full Moon Mirror."
It was also one of the cards Sarina used in the original story that never became a real card. When it first activates, it looks like pure set dressing—just there to heighten the underworld vibe and seemingly useless.
But as Aster and Jaden's duel against Sarina deepened, they realized that each time a monster on the field was destroyed, that thing would open one eye. They inferred its effect: every time a monster is destroyed, this card must get a counter.
Once it accumulates ten or more counters, you can send the Full Moon Mirror on the field to the Graveyard to activate a unique Field Spell from the Deck: "Infinite Fiend Mirror."
This is Sarina's killer combo. Her ace monster is "Dark Creator," and the Infinite Fiend Mirror is the Field that pairs with it. While the Dark Creator is on the field, its controller can Summon any number of "Dark Creator Tokens" to their field; every one of them has identical stats and monster effects to the original.
"My turn. Draw."
Kira said.
"I activate the Spell Card 'Take Over 5' and send the top five cards of my Deck to the Graveyard."
He pulled out five cards and sent them to the GY in order, then glanced at that eerie Full Moon Mirror.
Getting ten counters isn't that easy, but since it's the opponent's finisher, better to deal with it now and avoid future trouble.
"I activate the Spell Card 'De-Spell'," Kira said. "Destroy one Spell on the field. I target the Continuous Spell 'Full Moon Mirror.'"
Sarina: "!"
She was startled. Her Deck is a manifestation of her own power, a unique type brimming with the extraordinary; most of its cards don't exist on the open market, so there's no way the opponent could have seen them before. He shouldn't know what the Full Moon Mirror does.
She hadn't explained the Mirror's purpose at all—yet even so, he opened by blowing it up.
Just going off a duelist's card sense?
That's a scary intuition.
But Sarina wasn't about to be outplayed: "Then I activate my Set card, the Trap 'Card of Pandora'! When a card in your Spell/Trap Zone becomes the target of an effect, switch the target to this card. Then I draw two cards from my Deck!" (Anime card)
The green beam from De-Spell veered, skimming past the Full Moon Mirror and striking the just-flipped backrow card instead.
"Did you sense danger from the Full Moon Mirror? Too bad," Sarina smiled, drawing two. "Looks like it won't be that easy."
"True enough. You really is something else," Kira shrugged. "Then I'll Normal Summon 'Breeze Sphere' in Defense Position."
A gust spiraled up, and a small, cute bird rode a ring of air to hover over Kira's field.
[Breeze Sphere, DEF 1000]
"Then I set two cards to my backrow and end my turn."
Sarina pondered. Even going second, there was no offense, just a defensive posture. It reminded her of recent duel with Kaiser vs. Aster—he also went setting backrow, totally at odds with the image of the Cyber style.
Such similar duel styles… is there a connection?
"My turn, draw!"
Sarina set aside her doubts. For her, dueling is divination—peering into the opponent's fate. She believed everything would become clear as the duel progressed.
"I activate the Spell 'Pot of Greed' to draw two cards."
"Next, I activate the Spell 'Mirror Route'!" (Anime card)
Silver crosses rose from the ground, connecting to two colossal mirrors that thrust up from the earth. Her on-field Silver Spirit Ukyo, stood right at the intersection, reflected on both mirror faces.
"Mirror Route can only target a monster I control with 1000 or less ATK," Sarina said. "I choose 'Silver Spirit – Ukyo.'
That monster can attack directly this turn!"
She swept her sleeve and commanded:
"Go, Silver Spirit – Ukyo, direct attack the Duel King!"
The shikigami leapt forward, but midway it vanished—its reflection slipped into the mirror. A mirror rose behind Kira's Sphere, and Ukyo's image flew out of it, bypassing the front line to strike directly at Kira.
But just as Ukyo was about to land the hit, it slammed into an invisible barrier. It was as if airflow formed a transparent vortex, a shield that repelled the attack.
"What?" Sarina frowned.
"Don't be so hasty," Kira smiled. "Trap Card 'Air Barrier.'
While a Sphere is on my field, your monsters can't declare attacks, and this turn my monsters can't be destroyed by card effects."
"I see, an attack seal. In that case, even Mirror Route can't force a direct attack," Sarina said. "But do you think it'll be that easy?
I activate my Set Trap, 'Trap Stun'!
After activation, for the rest of this turn, all other Traps on the field are negated!"
Her backrow flipped again, a domineering wave of energy spreading. The swirling air of Air Barrier was forcibly suppressed; the shield was about to collapse.
"Later effects resolve first. Once Trap Stun applies, your Air Barrier is negated," Sarina smiled.
"Right, later effects resolve first. So before your Trap Stun resolves…"
Kira snapped his fingers.
"I activate my Set card, the Continuous Trap 'Limit Reverse.'
Special Summon 1 monster with 1000 or less ATK from my Graveyard in Attack Position."
Sarina's expression shifted slightly. "Limit Reverse's effect resolves first and slips past the negation from Trap Stun—"
"Exactly," Kira said. "From my Graveyard I revive—
—Synthesize Sphere!"
[Synthesize Sphere, ATK 1000]
"When Synthesize Sphere is Summoned, Special Summon a Level 4 or lower 'Sphere' from your Graveyard.
I'll Special Summon…"
Kira revealed another Sphere. The smallest Sphere whirled out from a vortex in the earth with a piercing cry.
"Air Sphere!"
[Air Sphere, ATK 400]
"Now the Traps finish resolving, and Air Barrier is negated by Trap Stun," Sarina said. "Mirror Route's effect: this turn, Ukyo can attack directly. No number of monsters will stop it.
Battle continues—Silver Spirit – Ukyo, direct attack!"
Ukyo lunged again—but a transparent ring of air swirled up once more. Ukyo smacked into it a second time and bounced back, scuffed and stunned.
"What now?" Sarina was puzzled. "Air Barrier has been negated…"
"True," Kira smiled. "But this time it's Air Sphere's effect.
While there is another Sphere on my field besides this one, your monsters cannot declare attacks."