Archer's Hrunting which traversed 4km in less than a second was calced at mach 15.
Actually under Mach 12.
Saber destroyed Hrunting.
This gives Saber mach 15 speed.
Which would only mean she can react around Mach 12.
She tripled her speed with Prana Burst when she went on to attack Lancer, and Lancer reacted to it, quite casually I might add.
It would have to specify movement or reaction speed. Far as I can tell that was so she could run faster, not hit faster. I'm sure people can dig up clips of the scenes.
Word of God also says that if Gil wished, he could finish the Holy Grail
War in a single night. This also implies that he has the speed
comparable to other servants, if not higher.
Actually it implies he has more power than the other servants and should be capable of killing them all easily. Which he kinda did in the animated versions with just using Gate of Babylon, which really didn't require any speed on his part. He just spammed attacks until they died. Of course in all the series he still ends up being defeated.
@ReiKai: The physical form that Mazoku project in the world of Slayers is actually a type of illusion to represent themselves in the physical plane, making them not much different from Heroic Spirits in that attacks affecting the physical plane can't harm them and high levels of magic or powerful conceptual weapons are needed to harm them. Both Mazoku and Heroic Spirits exist on the astral plane and only require their physical forms to represent their existence to those living on the physical plane.
Except Heroic Spirits can't fight
unless they project themselves physically. Mazoku do not have this issue. Xellos actually showed this when he impaled Seigram with his staff even though Xellos hadn't physically appeared in the material plane until after he'd struck, and then vanished again before Seigram was hit with Lina's Augmented Dragonslave.
Gaav did the same thing to Xellos later on by nearly cutting him in half before he even appeared physically, and even Xellos was caught completely off guard by Gaav's attack. This is a lot of clips of Xellos kinda getting knocked around, most of which is comedic. Around 3:43 is when they show him get ripped open by Gaav.
Things in the Slayers novels happen much quicker, and we also know from them that when using magic, the caster is automatically protected by a barrier near equal in strength to the spell they are casting. Xellos' main advantage is that he can teleport rapidly between the physical and astral plane. Teleportation is nigh-instantaneous. Xellos can also still attack while in the Astral plane, as he did to both Seigram and Valgaav in the anime.
Of course it would be nice to know if Xellos got to keep Galveira, the Darkstar Weapon also known as the Bow of Light. Which was the most powerful of the five weapons. Though he did give it to Lina in that last fight with Darkstar and then Sirius took them back to the Overworld. So I guess he won't have it.
Though I guess that's another thing in Slayers. City and mountain busters are the norm. A city-level attack won't even scratch Xellos' shields and the Ra Tilt
is brushed aside by just about every high-level Mazoku. It's possible Gil may be faster, but he doesn't have the raw power to take on Xellos. Gold and Black dragons are capable of blasting cities. Thousands of them were killed effortlessly by Xellos in a single move.