"Emerald and Mercury vs. Coco and Yatsuhashi" is a battle that occurred during the Vytal Festival tournament.
The match is part of the Vytal Festival tournament, and would determine whether Emerald Sustrai and Mercury Black or Coco Adel and Yatsuhashi Daichi would move onto the singles round. Like all Vytal Festival matches, the venue for the fight is Amity Colosseum.
Before the fight, Coco praises Emerald's clothes, with Emerald replying that she will try not to get blood on them. Yatsuhashi bluntly remarks that he can not guarantee Emerald will leave without a scratch, but Emerald curtly replies that she will not be the one bleeding. Coco seemingly approves of Emerald's confident attitude, commenting to Yatsuhashi, "I like her".
After the fight begins, Emerald and Mercury casually walk backwards into the concealment of the long grass in the savanna biome behind them. Coco and Yatsuhashi share a brief look before Coco turns Gianduja into its gatling gun form and sends a hail of bullets towards the grassland, trimming its grass short.
However, after all the grass has been cut, Mercury and Emerald are nowhere to be found. Coco and Yatsuhashi glance at each other in confusion. At that moment, Mercury appears from the sky, jumping to the ground to ambush them. Yatsuhashi manages to preempt his attack and pushes Coco out of the way, blocking his kick with Fulcrum.
As Mercury jumps back from his attack, Coco begins to fire on him with her gatling gun, but he is able to deftly evade all of her shots. He then lands in between his opponents, and lands a flurry of kicks on Yatsuhashi. As Coco tries unsuccessfully to get a bead on Mercury, he jumps up high in the air and lands on her gun. Yatsuhashi then tries to attack Mercury but he dodges and uses the force of Yatsuhashi's second hit to get behind Coco, thrusting her weapon into Yatsuhashi's stomach.
Realizing using her gatling gun in close quarters is awkward, she switches back to her handbag form and takes an ineffective swing at Mercury. Mercury jumps back and fires a pair of projectiles from his boots, which take an unpredictable, spinning trajectory towards Coco and Yatsuhashi, who deflect both shots without much difficulty.
However, when they turn their attention back to Mercury, they see that he has fired dozens of other projectiles from his boots, which spiral around him like a storm. He sends the storm of projectiles flying towards Coco and Yatsuhashi, landing around them and creating a haze of smoke.
When Coco and Yatsuhashi regain their composure and vision from the smoke, Mercury immediately appears behind them, grabbing hold of them and delivering a series of kicks to both. Emerald's kusarigama chain springs out from somewhere in the forest biome, ensnaring Coco and yanking her into the forest.
With his opponents separated, Mercury attempts to press the attack on Yatsuhashi, landing a kick on his opponent. Yatsuhashi pretends to use his sword but manages to grab Mercury by his neck and flings him far into the geyser biome. Yatsuhashi then jumps high in the air and attempts to land a devastating over-the-head blow with his sword, but Mercury is able to nullify the hit with his boots. The shockwave of Yatsuashi's attack causes the rocks in the biome to shatter all around him and the geysers to erupt, but Mercury is unaffected.
The two exchange a series of blows, with Mercury using a piece of rock from the shattered ground as a projectile, which Yatsuhashi deflects with his sword. However, in the melee, Mercury manages to hit his opponent down to the ground, his head landing directly above a geyser vent. At that moment, the geyser erupts. Disoriented and attempting to regain his balance, Yatsuhashi is easy prey for Mercury, who lands another flying kick on him.
On the other side of the arena, in the forest biome, Coco is slammed against a tree and falls down after being dragged through the air an incredible distance by Emerald's chain. Glancing around, she realizes her sunglasses have been broken, much to her chagrin. She realizes at this point that her initial assessment of Emerald was mistaken, and decides that, in fact, she does not like her.
Suddenly, a green bullet comes flying towards her, but Coco narrowly manages to evade it. Coco realizes that Emerald has taken position and is firing at her from the treetops. After dodging a burst of fire from Emerald's fast-firing revolvers, she turns her handbag back into its gatling gun form and sends a barrage of bullets into the foliage. Emerald moves between the trees with great agility, pausing occasionally to counter fire, before disappearing somewhere into the trees.
Cursing, Coco loses track of her target. Unexpectedly, from behind her, what appears to be Yatsuhashi emerges and calls her name. Coco warns him that Emerald is hiding in the trees, but at this point Port announces that Yatsuhashi has already been eliminated by Mercury on the opposite end of the field. Alarmed and confused, Coco turns back to see that Yatsuhashi is no longer there, and that she has been tricked.
Cursing again, Coco looks around cautiously, her hands wavering from fear or anger. Emerald emerges from behind and attacks her with her sickle before she has a chance to react.
With one blow, Coco is thrown clear out of the forest and lands in the center of the arena, next to the incapacitated Yatsuhashi. Emerald and Mercury join back up, triumphant, as Bartholomew Oobleck announces their win, to the great uproar of the spectating crowd.