Dark Blade of the Repentant

• Chapter 9 of the Covenant Campaign, as the item says.
• 3,500 Reservoir Anima. Players collect it from world quests and callings, and the weekly quest Replenish the Reservoir turns 1,000 anima into an Emblem of Renown.
• 10 gold at the vendor.

Gregor stocks twelve other weapons at the same price, such as the Dark Bulwark of Death's Vigil, the Ebony Soul Piercer and the Gavel of Dark Diviniaton. Reservoir Anima is capped at 35,000.

The order brings the character to the point where Gregor will sell the blade and completes the purchase. Tell the manager in live chat or Discord which covenant campaign your character is on and how far it is.

• A level 60 character with a covenant chosen.
• Enough Reservoir Anima, or time to collect it.

Is the sword a drop or a vendor item?

A vendor item. Gregor the Pallidblade sells it; no boss drops it.

Does it need a particular covenant?

The item names your own Covenant Campaign, chapter 9. It does not name a specific covenant.