Arboreans are a tribal race of plant humanoids that dwell in the deepest, most isolated parts of the thickest, darkest forests. Once inhabitants of the plane of Arborea, they were twisted and corrupted when Lolth blighted the plane during the Elf Wars. They are now brutal and highly xenophobic, despising civilization and outsiders alike. Each tribe is centered around a sacred grove where they bury their dead, planting trees, bushes, and other plants atop their graves. They believe that their ancestors' spirits inhabit these plants, and spread throughout their groves. They consider every part of their groves to be sacred ground, and will brutally attack anyone who enters.
Their customs demand that intruders be killed, and their blood used to feed the growth of their groves. Living captives might be cut and hung above their plants to slowly bleed to death as their blood drips into the shrubbery below. The skulls and bones of their victims are often hung at the edge of their territory as a warning to other would-be invaders. When faced with a significant threat, the arboreans will call upon their ancestral spirits to animate as plant terrors, enormous amalgamations of blood-drenched soil and plants.
Arboreans rarely work with other humanoids, preferring to keep to themselves, but powerful druids can sometimes forge alliances with them.