I am a sword user i dont like guns or bombs just swords and
i need suggestions of which sword goes well with OE or acheron? im currently going for the divine avenger because i like it the most but i think its too slow but powerful and i cant chose
heres are some surrgestions:
Wild Hunting Blade with acheron or OE
Leviathan Blade / Lionheart Honor Blade with acheron or OE
Fang of Vog with acheron or OE
Someone like Bopp can give some better information on this. But I usually pair up my Acheron with another Brandish. I would not recommend taking a normal sword with Acheron or Obsidian Edge since it wont be necessary. Only do this if one of your weapons happens to be a gun or bomb. That way you will have a back up weapon good for all cases. (You don't like those so any normal damage would be invalid here).
A Combuster about matches an Acheron's power so that could cover both shadow and elemental damages. Or you could take a Barbarous Thorn Blade/Finale Flourish. These are also quite powerful and can help cover piercing damage. Or if you are lucky with status effects, a Fearless Rigadoon/Furious Flamberge can also be useful.
If you want to stick with what you have selected in the OP, Fang of Vog completely. It's slow, but it will back up that elemental damage. Plus, the charge attack is overkill if you can survive using it.