"Yang vs. Mercury" is a battle that occurred during the Vytal Festival tournament.
The fight is the first match of the Vytal Festival tournament finals round. Like all Vytal Festival matches, the venue for the fight is Amity Colosseum. Unlike previous rounds, only the central octagonal area is within bounds, and contestants are disqualified if they fall onto the outer segments. As such, there are no biomes in this fight.
The fight begins when both Yang Xiao Long and Mercury Black land their first blow on each other, with Yang throwing the first punch in a haymaker and Mercury launching a jumping back kick. Mercury then rushes in, and attempts to aim for Yang's foot with a running jump back kick, but the latter leaps in the air behind him and attempts to land a shot with Ember Celica in a right jab.
The two each land a spinning back fist each that are both blocked, with Yang's subsequent left hook and jab are then continuously blocked by Mercury's forearms, while Yang ducks under Mercury's left hook. As Mercury prepares a palm strike, Yang fires off another jab, while her opponent shoots off a front kick, sending each other backward, only stabilizing themselves through a backflip.
Smirking, Mercury later dodges a barrage of rounds from Ember Celica while closing the distance, jumping into a downward axe kick blocked by Yang. He then leaps into the air to evade a low roundhouse and spinning back fist with a Dust blast, before delivering a kneeling flash kick to his opponent.
After she lands on her feet, Yang immediately boosts herself towards Mercury and attempts to launch several charged jabs at Mercury, who continues to block with his arms, before the two exchange a spinning back high kick. Mercury then forces Yang back by striking the back of her knee with a low side kick, before forcing her away with a front flip that sets up his Capoeira-style macao kick.
As Yang punches the ground, Mercury uses the momentum to perform a breakdance air twist, balance himself on one hand, and land two more chapeu de couro kicks to Yang, who continues to block the attacks. He then launches a spinning back high kick, with his right leg that pivots into an axe kick with the instep, cracking the pavement as Yang is forced to backflip away.
Mercury then launches a back kick, before dodging Yang's spinning back high kick as he sets up his next offensive combo. The spinning high back kick, followed by a regular spinning back kick and spinning jump back kick, forces her on the defensive, propelling himself upward as Yang staggers back from blocking the blow with her forearms. He then recovers from his perfect split landing breakdancing into a windmill flair and rushes in, only to see his roundhouse blocked with her arm before he suffers an uppercut into her left elbow strike, followed by her right jab.
After he falls flat on the ground, he finds himself shocked as he is forced to backflip away from the following salvo of rounds fired from her jabs, until one round nearly sends him off the arena, forcing him to propel himself back up the stage.
The silver-haired fighter then immediately launches a lightning-fast flurry of kicks, starting off with a triple turn kick at the legs, followed by two roundhouses and a front kick at the blonde's sides and arms. He then performs a spinning low back kick to force Yang's foot back, before landing both a high and regular roundhouse at her arms. Yang is forced to duck under his hook kick as she sees her left arm repelled by his front kick, which also blocks a round from Ember Celica. The following roundhouse thwarts a second left jab before forcing Yang back with a low roundhouse to the legs as she ducks underneath his spinning high hook kick before she attempts another jab.
Yang is forced back with Mercury's jumping side kick before she somersaults past his Dust round through a spinning axe kick. Smirking, Mercury then begins firing roundhouses in the air, with his adversary closing in. Mercury is still able to block a right jab, before responding first with his own jab followed by a front kick leading to an axe kick, before sending her flying with a high side kick, and finally knocking her down by finishing his combo with a 540-degree bolley roundhouse. This leaves her vulnerable to all of his rounds crashing down from above.
Just as he confidently walks away, brushing off his clothes, Yang, fueled by rage, begins her assault as Mercury mouths inaudible words.
Her first haymaker sends Mercury back, later dodging his subsequent high roundhouse, spinning high roundhouse and turn kick while landing rapid-fire fisticuffs bobbing and weaving into a Dempsey Roll technique. Her body uppercut and subsequent haymaker punches then proceed to break his Aura and knock him down on the ground, securing Yang's victory as she celebrates by raising her fist in the air.
When Yang wishes her fallen foe better luck in the future, it appears that Mercury launches an underhanded, surprise kick at her, forcing the victor to retaliate and fracture Mercury's leg.
As Mercury clutches his leg and cries out in pain, Yang attempts to trash-talk and justify her actions. However, the camera reveals that Mercury was merely walking towards her before she landed the hit, drawing the shock and ire of every single spectator in the arena, the combined negativity alerting the Grimm miles away.
As Emerald Sustrai rushes to his side, two soldiers, along with six Atlesian Knight-200 units order Yang to stand down, wholly unaware that she was caught in an elaborate ploy to frame her. She is later informed by General James Ironwood that she is disqualified.
- According to Shane Newville, series creator Monty Oum animated a "good portion" of the fight between Yang and Mercury and is credited as a Lead Animator on the episode.
- Mercury's projectile attack is an homage to a similar attacked used by Yuna in Monty's previous series Dead Fantasy.