Semi Useful Explanation.
A N/E sword would do +20%-ish damage against the appropriate Enemies.
An E sword would do +50%-ish damage against the appropriate Enemies.
And Vice Versa for those two.
These values are used for demonstration purposes and are probably not the real deal.
I think the only pure Elemental sword is the warmaster rocket hammer and its line. Though you can only obtain it with cash or energy.
Piercing weapons do pure piercing damage. It murders Beasts and prods Slimes.
Sound good enough?