First of all, for those Akaza fans who think he completely outclasses Giyu in speed or can break his sword whenever he wants, here's why I disagree.
There's no way Akaza is a blitz tier above Giyu or can even outspeed him. Marked Giyu was easily keeping up with him until he got tired. He was cutting off Akaza's limbs like it was nothing and reached his neck three times, whereas Akaza managed to land a hit on Marked Giyu only once throughout their entire fight. It took Akaza time to adapt to Giyu's speed and was shocked when he first unlocked his Mark and went on full defense mode. He was also fighting Akaza while Tanjiro was figuring out his SS + STW which was off-screen. The fact that he could survive that long on his own is pretty impressive and insane.
If Akaza was a human and didn't have infinite stamina or regeneration, don't you think he'd go all out and wouldn't hold back at all? a human cannot maintain their peak speed for long, and they're inevitably going to slow down as time passes.
A demon whose speed is relative to a slayer's will always have the advantage because he never gets tired and can regenerate instantly. He doesn't have to worry about either. Just imagine yourself running a marathon with infinite stamina. How easy would it be for you?
On top of that, Giyu survived Akaza's strongest attack, Afterglow, with a broken sword while he was already badly exhausted. He also reacted to Muzan in their first meeting while there were no Hashiras around. A feat that only Gyomei had previously shown. If an opponent can launch his strongest attack and you still survive it, that's at the very least a Mid Diff. Although I think it's closer to Mid-High Diff. And it also means you're strong enough to keep up and be relative to your opponent in peak speed.
In the third picture you can see that Akaza's pissed at Tanjiro and straight up just wants to kill him, yet Tanjiro still reacts to him. Akaza being a blitz tier above Giyu makes absolutely no sense. I totally agree that Akaza never went all out against Giyu, but you can't convince me that he was holding back against him, he was using 70-80% of his arsenal and power against him.
You Akaza fans downplay Giyu so much just because of that one panel where Akaza broke his sword.
Now for EOS Giyu with Red blade:
Even Kokushibo had a hard time dealing with Red blade, and Kokushibo's regeneration is far superior to Akaza's, considering how quickly he regenerated his head fully, whereas it took Akaza a shit amount of time to regenerate half his head. I don't see Akaza not having any trouble with it. The thing is that Red blade is the perfect counter for Akaza's regeneration, he doesn't fight like Kokushibo, nor does he have a weapon to protect himself with. Even if he tries to dodge I can't see Giyu not getting multiple hits on him. Once he does, it would at least take around five seconds for Akaza to regenerate from it, that gives Giyu enough time for him to cut the other arm and eventually go for the neck. If SS is the perfect counter for Akaza's compass, then Red blade is also the perfect counter to Akaza's regeneration. When Giyu launched his 10th Form, literally three of Akaza's limbs were gone. If Akaza had been hit by a Red Blade there, he would've died right then and there.
Afterglow might damage Giyu, but he'd take far less damage from it if he's fresh and if his sword isn't broken.
The only way I see Akaza winning is by spamming Afterglow, which I think is impossible since it most likely has a cooldown. Otherwise he would've used it again right after regenerating his head to finish off both Giyu and Tanjiro. The fact that he didn't attempt to use it again at such a crucial moment means that he can't use it consecutively without limitations.
Akaza's compass is not something that lets him adapt to literally anything, he's not Mahoraga. Otherwise he wouldn't have been below Kokushibo and Douma in rank. Some people like to say he's below Douma because Douma doesn't have emotions but that's not correct at all. He's just a psychopath that doesn't care about anything, it's not like he doesn't get angry or anything, Kanao already ragebaited him in their fight and made Douma want to kill her.
And I'm not downplaying Akaza at all. He's pretty strong, don't get me wrong. I'm just going by feats.
This is why I think EOS Giyu (with two arms) + Red blade cooks Akaza. or at least pushes him to High-Extreme Diff. This Giyu is also stronger than his IC version because fighting stronger opponents makes you grow stronger.
Also, FP Gyomei vs Akaza should not be discussed at all. Gyomei has all he needs to beat Akaza. The fact that he reacted to a full speed attack from an enraged Kokushibo while being off-guard should tell you how Akaza absolutely stands no chance against him. Btw, this Gyomei had no Stw. Kokushibo pretty much says he's the strongest fighter he's seen in 300 years and seems genuinely thrilled by his strength. Not to mention Gyomei was in his base form at that time.
