Well...it would be nice if you could...
GIVE US SOME MORE IMFORMATION.
Like your playstyle, or if you want something more specialized, or if your enjoy bludgeoning something to death, or if you are interested in specifically doing some unspeakable horrors within the clockworks.

Just a normal hack and slasher?
The Leviathan blade is a normal sword of Hacking and slashing.

Got a little spring in your step?
The Final Flourish puts Finess and dignity into your swordplay.

Want every swing to feel like you are hittting someone with a train?
The Sudaruska ensures your shoulder will ache immensely.
If you have a cold attitude, the Triglav Freezes as well.

Do you like setting the forces of nature upon your foes?
The Brandishes final forms allow you to wield a specific element from your fingertips.

Do you like MEAT CHUNKS?
Fang of vog, dread venom striker, and wild hunting blade will cut EVERYTHING UP with rapid fury, with some...side affects.

Do you believe in a higher spiritual power?
Divine Avenger or the Gran Faust for the inner believer within you.

Now just to be fair, THESE ARE ALL MY OPINION and I don't need someone biting my buttocks on how one sword trumps another.or why I forgot a sword.
They are all fantastic blades within the right hands.

I recommend that you go the wiki and look up the swordmaster guide for more information.

But since you are simply asking for "what 5star blade I should make" without telling us anything much...

The leviathan blade. Because it's the ultimate generalizer. Not good versus everything, but not bad versus everything.

Really?

How deceiving. Upon review it behaves exactly like a calibur. strange.

In that case it would be an elemental sword to challenge the combuster brandish, maybe even being superior.

I think you should make triglav as your first sword so that you'll be more interesting than the other brandish-knights.

You goofballs and your brandishes :P

It's seriously kind of a bad weapon. Like the power you get out of zero skill is huge but also you can just learn how to play the game and be better off because of it. Brandish is probably the "right call" for the op but if I run into them I'd be stoked to see grintovec on them instead of night blade. Like you have no idea, friend request right there.

Just so you know, Brandishes release a wave that Enemies 'ride' apparently. The freeze nullifies that. It's no biggie, I hear it's great for the final boss dungeon.

Firethornz, I already gave you the link to my sword guide. As it explains, freeze on a brandish is a hindrance, and Combuster/Voltedge is better than Glacius. This is still true in the "final boss dungeon" known as Firestorm Citadel, even though most of the monsters there are immune to fire. That said, Glacius is not terrible.

Edit: Now you are talking about Leviathan Blade. Like Glacius, that's not terrible but not great. Whether you want an "all-rounder" or not depends on your other weapons, as I've already pointed out in my sword guide and in post #2 above. Are you going to tell us your other weapons or not?

since I already have the 3* Iceburst Brandish and I need only 1 Elite Orb more for the Blizzbrand, I think I will go for the glacius!

This is the wrong reason to upgrade an item in Spiral Knights. The costs of making an item dramatically increases as the star-level goes up. For example, the cost of a 5-star recipe is much more than the cost of its 2-, 3-, and 4-star recipes combined. And let's not even talk about heating a 5-star item.

So don't follow through on an item unless you really want it. Even if you had the 4-star freeze brandish, it would not be too late to switch to another alchemy path. But of course the choice is up to you.

Your orb question is a frequently asked question. My carefully composed answer is here. The short answer is: Buy them, because the alternatives are even slower.

At the Supply Depot you can buy three 4-star orbs for 400 energy.

But from other players, for example through the Auction House, you can buy a single orb for much less than 400 energy. It won't be as low as 400 / 3 = 133 energy, unfortunately. But if you want only one orb then that's a fast way to get it. Then you can spend your time getting more crowns.

100 energy is about 9000 crowns this week. Therefore 133 energy would be about 12000 crowns. By selling at 13000cr, it looks like the seller is asking for a modest profit. But remember the AH listing fee is 10% of the sale price = 1300cr. So by selling at 13000 crowns the seller is actually losing money slightly. You probably should buy.

The orb thing is more complicated than just the numbers.

People sell orbs cheaply so that they can force others out of the market. They sell cheaply until others start to lose money and cannot afford to keep up because they have a relatively large sum of crowns (think on the order of multiple billions) and in doing so will get to dominate the market for a while, making a couple hundred thousand (or more) a day off of each rarity they are selling-- easily enough to counter their losses.

Really you should just avoid their silly yet profitable games altogether and find your orbs, buying them with energy if you must.

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Glacius is a totally fine sword to go for. It accomplishes roughly the same thing that acheron and combuster accomplish, but allows for the user to freeze monsters and trap them there, spamming charges over and over. The only thing it doesn't do is kill things a bit faster (via fire/extra damage + "riding the wave"), which you don't even need to do (the killing, I mean) on most runs since your entire party will just charge through and murder everything before you can hope to get there in an attempt to be the knightliest.

By killing things slowly you also get to partake in more action per amount of walking down paths and loading which is a huge bonus on the levels where brandishes really shine.