well right now i've got ascended calibur and warmaster rocket hammer but once i get levithain, what sword should i get (shadow damage and peirce damage i need right now, rocket hammer is elemental)
After levithain
Don't bother upgrading your Calibur. Once you have swords of two or three non-normal damage types, you will (almost) never use a normal sword again.
You might think that stopping work on the Calibur is a "waste" of the resources you've already spent, but keep in mind that more than half of the cost in making a 5-star item comes in the final upgrade from 4-star to 5-star. So you haven't really wasted much resources yet.
One other comment is that the upgrade from Ascended Calibur to Levi is mostly cosmetic and only offers a modest damage increase. Reach is exactly the same though the Levi's models is waaaay bigger & longer. Knockback might increase a bit (I did not really notice), but many would consider this a negative anyway. Look a the Wiki damage numbers for Ascended Calibur vs Levi (it is very minor upgrade). On top of that a fully heated Asc Cal will out damage a L1 Levi, so you are paying a bunch to nerf your blade until you can get it heated back up. I did finally upgrade mine, but it was a very low priority & I use it only rarely (Vana mask mostly).
Normal damage is not useful after youve got some good special damage weapons.For Shadow damage get Achereon and for Pierce damage get the Barbarous Thorn Blade. No doubt those are the best weapons for that stuff.
...you've been going this long without damage variety?
Sod Leviathan. Get a Silent Nightblade and Grand Flourish before you upgrade it.