RWBY fan base has it's share of toxic fans. Truly every fanbase does but RWBY's is crazy! They actually think Yang is anywhere near the level of Super Saiyan's, the strongest Super Heroes, let alone One Punch Man... She isn't even close. She got beat by a small petite girl who did ballerina all over her!
Theoretically IF Yang survived a hit she can deal double the damage back but ONLY IF she hits the target. And IF she can survive the damage she is taking, she is tough but no where near invincible! Yang is notoriously easy to angry, reckless, and predictable. Her level of skill is pretty average and very low compared to master fighters. Yang is too straightforward and not overly dynamic. Neo just dancing and twirling around her with overly flamboyant delayed moves, much slower than better trained martial artists from other series, and she totally pwned Yang! Just picked her apart before slamming her into the short ceiling of a train knocked out Yang... I'm sorry that was pathetic for someone who RWBY fans think is a Hulk or Saiyan. Yang is overated.
Mercury's fight proved how little time and damage it takes to deplete Yang's very limited supply of Aura. And Mercury lost intentionally by the way all part of the plan to frame Yang. Once her Aura's gone she is vulnerable to finish. And powerful enough attacks can pierce through and completely negate Aura. We saw this with Adams blade but many things from other universes could do this easily.
Examples of other series fighters, Batman would take down Yang no problem because he is just that skilled at grapples, feints, take downs, dodges, counters, submission holds, pressure points and so on. Batman has mastered every known martial art. Now take, Black Panther who is that skilled and his panther strength rivals the super soldiers like Captain America, who is also a master of every known world martial art, just like Batman and Black Panther, and even though all 3 of these fighters aren't as strong, they would take down Yang. All 3 of them are skilled at dodging and countering bullets as well. Batman's Batarangs would damage the Ember Celica not allowing it to fire, Caps shield is bulletproof and absorbs powerful hits, Black Panthers armor is Vibranium and bulletproof.
Spiderman is extremely skilled as a fighter. Not as experienced but also even stronger than these 3 and has the spider sense to dodge Yang's attacks. He has webbing that can temporarily hold Hulk and gunk up gun barrels. Spiderman would destroy Yang even if the webs only just slowed her down, but they would do much more. She couldn't move at all against his strongest webbing. Better fighters can knock Yang out by simple pressure point, submissions holds, of just knock her head into a wall like Neo did... And you don't even have to be a world class fighter like Wildcat, Black Canary, Green Arrow, Black Widow, Batman, Robin, Nightwing, or Red Hood to do it! All fighter examples who fight super strong mutants or metahumans and they win by skill, wits, and not getting hit by the raging beast's or brute human's predictable attacks! There's many more in comics who do this same feat but you get the idea.
Now take that kind of martial arts mastery, speed, agility, combat experience, feint fighting style to deceive and pick apart a reckless fighter like Yang, only now make this fighter even faster, more athletic, able to use powerful magic, and who also gets stronger the more damage she takes, unleashing limit strength rivaling Super Heroes and Super Saiyans! Enter Tifa Lockhart from Final Fantasy 7. She literally has no limit to what she can lift in her limit form suplexing mountain sized God-Machines called the Weapons. Lifting not enough? Okay it gets better Tifa grabs them with one hand and flies sky high before hurling them down to the ground! Superman caliber right there! Those attacks aren't even her strongest! Her best attack is a Falcon Punch on steroids, her Final Heaven Punch attack! Mercury's attacks prove just Tifa's normal attacks would drain Yang's Aura and then the better skilled, stronger fighter would take out Yang easily.
In the FF 7 movie Advent Children Tifa beat the crap out of Loz, who is a Sephiroth remnant possessing all of the original Sephiroth's strength and speed. Tifa won the first fight. After a short break Loz had a new idea he used his over-sized taser fist weapon bigger than his hand and taser punched Tifa in the back of the neck! Even Superman and Hulk have been knocked out by strong tasers so this does not discredit Tifa in any way. Loz was lucky and pulled a smart move against a foe he knew he couldn't beat! Tifa was already knocked out but he smashed her through a concrete pillar next before escaping with Marlene and the Materia. Later Tifa woke up with Cloud and was totally fine! Not injured in any way what a Tank! Tifa is a durable Tank!
The story wouldn't have happened if Tifa stopped Loz right away and she would have if not for the unexpected taser. Tifa was beating Sephiroth's strength and speed in a martial arts fight! Also Tifa is NOT a glass canon her defense and HP stats are right in the middle of the group and she takes hits no problem. Even Aerith, Vincent, and Cait Sith who have the lowest Defense take hits just fine! None of them are "glass canons" as Death Battle wrongly claims. End of the FF 7 game Tifa and her friends battle Sephiroth who ascended to God-hood! Final Fantasy heroes battle Gods or God-level monsters, endure hits from the strongest beings in the universe, and defeat them to save the world! Feats right in the top list of any other series heroes. Just let that sink in.
Tifa would annihilate Yang Death Battle got it wrong. Their research team had official evidence proving Tifa's victory but the head two spokesmen Wiz and Boomstick changed it up, left out that key research, and went with their own biased outcome to promote their new partner RoosterTeeth. ScrewAttack is financial partners with them make sense now?
Yang is NOT invinciple by any means and her Aura is extremely limited! Her semblance which increases her strength when she loses hair or gets pissed off ONLY increases her offense. It does NOTHING for her defense, durability, or her predictable rampage that better fighters will easily pick apart.