Grimwarder

A Grimwarder is a spectral monster that only appears in chapter 3 and chapter 6 of the Shadows of Amn campaign.
If you have sided with Aran Linvail in chapter 3 — when you undertake the third task for Aran, two of them, along with two Grimward Archers, are encountered in the Lower Tombs guarding the entrance to Bodhi's hideout. Two more are also found within Bodhi's Lair along with two more grimward archers and three Fledgling Vampires.
When you attempt to retrieve Imoen's soul during chapter 6 — one is found battling with Drizzt Do'Urdens crew and one is also in battle with Arkanis Gath and his band of Shadow Thieves. Two more will appear in the final fight with Bodhi in her lair.