Rellana's Twin Blades is a Light Greatsword in Elden Ring. It is a brand new Light Greatsword in the Shadow of the Erdtree DLC. The Rellana's Twin Blades scales primarily with Strength, Dexterity, Intelligence and Faith and is a good Weapon for Int/Faith Builds.
The Rellana's Twin Blades weapon can be found at the following location: Trade Remembrance of the Twin Moon Knight with Enia at the Roundtable Hold, to receive this weapon.
Weapon Skill: Moon-and-Fire Stance
This weapon cannot be infused with Ashes of War
Rellana's Twin Blades can be upgraded by using Somber Smithing Stones
This is a paired weapon, meaning you only need to have one copy in order to dual wield it.
The sword used depends on the hand it is wielded in; this allows dedicated Int or Faith builds to use only the sword which suits their build and potentially pair it with an appropriately-infused Milady in the other hand. However, this also means that it cannot be dual wielded to use a pair of the Int swords, the left hand weapon will always be the Fire (Faith) blade, even if two sets of Rellana's Twin Blades are equipped.

Attack
Guard
Scaling
Requires
Skills: Moon-and-Fire Stance
Damage Type: Standard/Pierce
FP Cost: FP 10 - 25
Weight: Wgt. 8.0
"Carian light greatsword embedded with blue glintstone. Weapon of Rellana, the Twin Moon Knight. Two swords as a single armament. When two-handing, a straight sword engraved with golden flame will be carried in the left hand. Here, and here alone, were moon and fire ever together. "
Horned Warrior's Greatsword is a Curved Greatsword in Elden Ring. It is a brand new Curved Greatsword in the Shadow of the Erdtree DLC. The Horned Warrior's Greatsword scales primarily with Strength, Dexterity and Faith and is a good Weapon for Builds that use Strength and Faith.

Dancing Blade of Ranah is a Curved Sword in Elden Ring. It is a brand new Curved Sword in the Shadow of the Erdtree DLC. The Dancing Blade of Ranah scales primarily with Strength and Dexterity and is a good Weapon for Dexterity Builds that attack rapidly.

Falx is a Curved Sword in Elden Ring. It is a brand new Curved Sword in the Shadow of the Erdtree DLC. The Falx scales with Strength and Dexterity.

Horned Warrior's Sword is a Curved Sword in Elden Ring. It is a brand new Curved Sword in the Shadow of the Erdtree DLC. The Horned Warrior's Sword scales primarily with Strength and Dexterity and is a good Weapon for players who like paired weapons or Curved Swords but don't want to farm two.

Spirit Sword is a Curved Sword in Elden Ring. It is a brand new Curved Sword in the Shadow of the Erdtree DLC. The Spirit Sword scales primarily with Strength, Dexterity, and Intelligence and is a good Weapon for INT characters in the look for a sword.

Fire Knight's Shortsword is a Dagger in Elden Ring. It is a brand new Dagger in the Shadow of the Erdtree DLC. The Fire Knight's Shortsword scales primarily with Strength, Dexterity and Faith and is a good Weapon for Fire-based builds.

Main-gauche is a Dagger in Elden Ring. It is a brand new Dagger in the Shadow of the Erdtree DLC. The Main-gauche scales primarily with Strength and Dexterity and is a good Weapon for performing quick slashes.

Golem Fist is a Fist in Elden Ring. It is a brand new Fist in the Shadow of the Erdtree DLC. The Golem Fist scales primarily with Strength, Dexterity, Intelligence and Faith and is a good Weapon for players that want to be able to attack at range, as well as melee.

Madding Hand is a Fist in Elden Ring. It is a brand-new Fist in the Shadow of the Erdtree DLC. The Madding Hand scales primarily with Strength, Dexterity, Intelligence, and Faith and is a good Weapon for inflicting Madness.