Final Guard is a difficult move that is specific to Bahamut's make-up. You see, the Beyblade layer shifts tooth by tooth up until the Burst. When Bahamut's layer shifts three times it aligns with the underlying metal layer in a way that creates a powerful defense.

You have to know how and when to use it though, since it also means that Bahamut is very close to bursting itself.

[ Should he be explaining his special move so in depth to anyone? Probably not. But this isn't home, so who cares. ]

But that's Bahamut. Every Beyblade has unique properties and every Blader has their own launching technique that combines with those properties, so special moves come in any kind of variation. It's all about knowing your potential.

With Ragnaruk here, the interesting part is probably it's performance tip. [ You know, the lowest part of the Beyblade. ] It's very low-friction, which makes it prone to slipping out of the stadium. But on the other hand, it means it's less vulnerable to attacks and can just use the push to pick up speed instead of taking damage.

That's what I would work with to come up with a move, but of course there's all kinds of aspects that could amount to one.