Graycloak's Pact Blade

is found in the Box, which is granted to those that purchase the Hero of the North or Guardian of Neverwinter Packs. The box will always grant a class appropriate weapon, and this is the one for a Scourge Warlock.

The 's Offense slot starts pre-filled with a enchantment which can be removed or replaced as normal. While slotted this adds the trait (all three modifiers at once):