I'll give an unbiased look at both sides here.
Grievous's main advantages are pretty straightforward. He has the AP and durability advantage over Yoru's normal physical stats and most of her weaponry. He has better combat experience and his skill as a Jedi killer settles the skill part of this fight in his favor. He is trained in multiple lightsaber forms, can fight with four arms, can attack from awkward angles and has droids to add pressure and interrupt Yoru's setup. In a close range fight Yoru is very clearly at a disadvantage because Grievous can pressure her immediately and does not need much setup to win.
That being said, I do not think Yoru's side should be dismissed as simply as "Grievous rushes and wins" since Yoru has her own set of win cons and counters, especially through her weaponry and attack speed. Her Right Gun Gauntlet is weaker than Grievous in AP, but it still scales far above 15 megatons and fires Mach 6000+ projectiles. That means even with speed equalized, Yoru's weapon and projectile speed is still a separate advantage that Grievous has to deal with. Even if this stops the match from being added, it is a point that I must bring up because it plays a huge factor in this fight, so take it as you will. The Gun Goddess is even worse for him since it reaches Relativistic attack speed and massively outscales him in AP.
The Right Gun Gauntlet is dangerous here because the shots are not something Grievous can comfortably treat like a normal visible attack. The shots are invisible, so Grievous does not really have a direct counter like Extrasensory Perception, Precognition or any Analytical Prediction listed on his profile. His best counterplay would be moving unpredictably, aim dodging Yoru's arm movements, using his droids as cover or distraction or rushing her before she can keep firing, bad idea but with his kit, its possible. This gives Yoru a better ranged win con than the Gun Goddess. Even if the Right Gun Gauntlet is around 5x weaker than Grievous, it can still badly damage him if it lands in a vulnerable area, especially his chest cavity. Grievous's profile specifically notes that his internal organs are vulnerable if his chest is opened, so a clean shot from Yoru could become a serious problem, especially since the knockback or direct explosion from the shot would naturally cause internal damage and be terrible for his case.
Yoru also has other ways to complicate the fight. Her weapon creation and transmutation can turn things she perceives as hers into weapons and Yoru can create weapons without needing direct contact. This means there is at least a possible argument that she could weaponize nearby objects and structures or potentially some of Grievous's droids if she can establish the ownership condition. She also has Room 606 Sword which gives her a huge LS advantage, which is stupid and should be energy projection but whatever and Gun Goddess, which would absolutely one shot Grievous if it successfully activates and lands, with no hope of him even aim dodging once she fires.
However Grievous still has very strong counters to most of this. First, Yoru's strongest options are not equally as reliable. The Gun Goddess is her best AP win con, but it takes time to activate, summoning the devil itself, contracting the fingers away and taking a few seconds, maybe at most 20. Grievous is the kind of fighter who would aggressively pressure her rather than allowing her to set up freely. Second, while the Right Gun Gauntlet is dangerous because of its attack speed and possible visibility issues, Yoru still needs to aim and fire it. Grievous can keep an eye on her arm and force close combat, use droids to divide her attention as well as use his own ranged equipment while advancing. Third, Yoru's transmutation still depends on perception of ownership, so it is not an automatic "I see you, I own you" like Makima most of the time, at least not in this key.
So the battle comes down to this;
Yoru has the more explosive win cons like the Gun Goddess which one shots, Right Gun Gauntlet gives her a fast and hard to read ranged option, Room 606 Sword gives her a massive LS advantage through slashes and her weapon creation could turn the battlefield or droids into tools against Grievous. If she survives the opening and gets breathing room, she can swing the fight in her favor.
Grievous however, has the more (imo) reliable win cons. He starts only 20 meters away, has a clear AP and durability advantage over Yoru's base stats and most of her weaponry, has superior melee skill, has four lightsabers and an unorthodox fighting style and has droid support to keep Yoru distracted. His best route is to rush her and interrupt her stronger setups by force close combat and kill her before Gun Goddess or repeated Gun Gauntlet shots become decisive.
Overall tho I think both sides have valid win cons, but I would still say Grievous winning is just more likely to me. Yoru's attack speed advantage with the Right Gun Gauntlet and Gun Goddess makes her much more dangerous than y'all may be giving her credit for and Grievous does not have a perfect counter to invisible or hard read shots. But Grievous's AP, durability, skill and droid distractions, I do not know what the droids scale to in AP, give him a better path to victory before Yoru can fully capitalize on her stronger weapons.
So I'd probably say Grievous. Better luck next time Yoru when I can finish my CRT's.
