So, the Sanctuary alchemy machine only gives armors, yes? Now bear with me here. How about there be a new piece for each SL level, which you get for combining 3 materials of the same boss? It would be a bit like this:

Snarbolax: 3 Nightmare Manes -> 1 "Dark Piece"
Queen: 3 Celestial Ores -> 1 "Holy Piece"
Twins: 3 Gremloniums -> 1 "Rocky Piece"
Vana: 3 Maiden Tears -> 1 "Oceanic Piece"

You can do this in the Alchemy Machine.
They would have to cost 800 CE and 10k CR to make.

Now, here comes the fun part: Using these "pieces" to craft amazing 5* weapons: Not enough to be OP, but enough to be "better" than the others.

1 Dark Piece and a Sealed Sword would be crafted into 1 ""Zulfiqar".
1 Holy Piece and an Sealed Sword would be crafted into 1 "Dyrnwyn".
1 Rocky Piece and a Sealed Sword would be crafted into 1 "Claymore".
1 Oceanic Piece and a Sealed Sword would be crafted into 1 "Excalibur".

Zulfiqar would be shaped like a black pole, with the vortex lines from Graviton Vortex flowing into it. It would deal half shadow, half normal on regular swings. It would be a 3 strike combo, just like the brandish lines with 5% more damage than the Acheron, and a little slower. What would be different would be its charge. You would take a step back, and then, like the FoV charge, release a tornado around you with just shadow damage. It would also release Acheron charge lines to the north, south, east, and west; however, the explosions will reduce in damage as they go farther and farther away from the tornado.

The Dyrnwyn would be shaped like a DA, except the whole thing would be golden even the blade in the middle, without the ribbon on the hilt, and a little slimmer. 3 swing attack, and 5% more than a Combuster. Half elemental, half normal, with a small chance of lighting the enemy on fire on the normal strike. Basically, all these swords have the same attack combo. The charge would go like this: The Dyrnwyn would be raised up, like in the WRH charge, and then slammed into the ground, without the leap forward. It would create a massive explosion and deal radial damage, like a bomb, and will light everything on fire.

Claymore is a huge hammer, like a sledge hammer, a huge stick with a huge anvil as the head. 3 swing attack, normal damage. It would have a good chance of stunning enemies, and a 25% (?) chance of hitting a critical on the enemy (brown numbers). The charge goes like this: Same as a Calibur charge, except you are taking the hammer and swinging it around, like in the Olympics, where they swing with a weight to build up momentum, and then launch the weight to see how far they can throw it. This is like that. Except without any throwing. You turn 3 times, and deal 200-300 damage(?) every time you hit, but there's a little knockback: like what you would get when you half the knockback of a CIV charge.

Excalibur is a sword. A big, black and gold sword. It's hilt would be golden, with black stripes running around it. The blade would be straight, but it would be very majestic looking (idk, horrible fashion on my side, help me out here). The whole sword would glow. It has a 3 swing charge, but it has a chance of dealing any kind of damage with normal. I guess there would be a check box on the sword which you can edit in an arsenal station to choose which type of damage you want to deal. That's great. The charge would make you lift up the Excalibur above your head, and it would start glowing (minimally to reduce the team rage), and then release a wave of energy throughout the whole room, like a bomb radius of a little bigger than a Shivermist, with a little knockback. It would deal a split between normal and whichever damage you have chosen. If you have more than 1 chosen, it will deal a split between normal and one of the damages you've chosen.

Of course, all these charges won't do incredible amounts of damage, like 2000 in one shot, but they are a little op, so if you have any ideas on how to improve this, please, go right ahead. Constructive criticism is appreciated.

I'm sleepy right now, but I'll try to develop it tomorrow, when I'm more awake.