You will desire multiple sets, and to set your stats most of the time at 200 DEX.  Depending what you are fighting, you will be switching around between END and LUK for 200, and WIS for the last 45.  END is vital in the Inn at the Edge of Time, not so much outside of it, at least not for a Doom Knight.

Best Primary Weapons (if you're stacking DEX)

Uragiri III or Verraad III (Evil)

Unreal Twin Blades of Doom (Darkness)

Ultimate Twin Blades of Destiny (Light)

Exalted Apotheosis (Good)

Jade Cleaver of the Lone Tree (Nature)

Uncalabra III (Silver)

Frostscythe III (Ice)

Great Dragon's Claw III (Fire)

Lance of Awethur III (Stone)

Sea Chicken's Conquest III (Wind)

Chaotic Blade of Swordhaven III (Energy)

Elite Knife of the Sunken Rose III (Water)

No other weapons are really worth getting IMO unless you're a collector like me