The Followers of the Code
by Marc SaindonRanger Serial Killer conclave (npc antagonist faction) of Karameikos
They might hunt in the dark alleys of Mirros, or lurk in Dymrak Forest waiting for unwary campers, but in either case, their favored target is... you.
Rather than be empowered by nature, they likely get their spells from some connection to the Unseelie, Ravenloft, or the Nightmare dimension. 8th level Land's Stride might work a bit differently, with the Dark Ranger ("Slasher") moving at an increased, or even running speed, but maintaining basic walking movement, as if distances stretch out supernaturally (think of 'the Shape' in the Halloween movies).
Another possible idea is to create a chaotic aura around the Slasher that causes Disadvantage when using standard weapons, while improvised weapons oddly function at Advantage (allowing creative combat). This might count as the Dark Ranger's fighting style. An odd signature weapon, such as a bladed glove, might also be worked in as an Advantage.
usually, Slashers can't read Ranger signs or trail marks, as they are not Rangers per se (unless DM decides otherwise in the wilderness setting), although they can recognize each other as Followers of the Code or spot potential slashers.
(pic from from Ravenloft 2e https://www.enworld.org/threads/reading-ravenloft-the-setting.678626/page-35)