For this build u will need a lot of dexterity, that is why I should suggest your starting class mercenary because the mercenary starts with the most dex but it doesnt matter in the begin.
Starting item doesn't matter either.

This build isn't difficult to use. This weapon while duel wielding is very fast.

Ofcourse like what the title is this build you will need the Sellsword twinblades.
The mercenary starts with the Sellsword twinblades.
or LOCATION: Found behind the Black Knight in the swamp area in the Road of Sacrifices. Near Halfway Fortress bonfire.

To use th sharp gem you will need the Farron coal wich can be found at Road of Sacrifices: At the Halfway Fortress bonfire where you first meet Anri and Horace go down and drop down from the ledges on the right side, keep going straight along the right wall and enter a doorway in the end. Turn left and you will see a Black Knight guarding a few bodies, the body at the end of the hall holds the coal.

• Upgrade: Infuse with sharp gem and then buffed to +10.
  
• Location sharp gem early game: Undead Settlement
  Guaranteed drop from the Crystal Lizard found on the ledge above the Dilapidated Bridge bonfire.
  
• Can also be farmed in the first DLC Painted World of Ariandel , dropped by Corvian Knights.

For this build you will need 4 rings:

• Chloranthy Ring for the extra stamina recovery. Location: Found in Undead Settlement. After defeating the Demon alongside Siegward of Catarina, scale the nearby building and exit into the adjacent tower by jumping from the roof. Maneuvering down the tower, the ring will be located under several wooden boxes near the Mirrah Armor Set.
  
  
• Flyn's Ring does Lowering equip load increases attack power up to 15%. Location: In the area where you fight the Fire Demon with Siegward of Catarina. On the top of a roof
  
  
• Pontiff's Right Eye Boosts Attack Power , as long as attacking persists. Location: Located in the Irithyll of the Boreal Valley. Drops from the Sulyvahn's Beast.
  
  and the last ring
  
• Lloyd's Sword Ring Boosts Attack Rating by 10% when HP is full. Location: On a corpse inside Cathedral of the Deep, near the entrance on a ledge next to the Giant who attacks you when running by.

For armor it really doesn't matter, be aware for the Flyn's Ring for the extra damage boost.

Try to go for this soul levels

• Endurance: 40
  
• DEX: 60
  
• VIGOR: 40

U can use in your build magic, pyrmoancy or miricales.
I stick with Gold pine resin or Charcoal Pine Resin for invaders (pvp) and
Gold Pine Bundle or Charcoal Pine Bundle for pve.
But that is up to you.

Thankyou for reading this guide, it was my first guide ever.
And rekindle the first flame ashen one!!!

Information: https://darksouls3.wiki.fextralife.com/Dark+Souls+3+Wiki