A high-detail digital painting of a three-headed serpent dragon faction boss, featuring a realistic and anatomically accurate body structure with two legs and two arms. The dragon's skin is a complex mosaic of emerald scales and golden-yellow leathery membranes that resemble giant autumnal leaves. The art style is defined by thick, bold ink outlines and a rich gouache texture, creating a weathered and ancient appearance. Dramatic golden rim lighting cuts through a swampy, fog-filled forest backdrop. The three heads are posed in a triangular defensive stance, mouths agape to reveal realistic anatomy and sharp teeth. The overall mood is epic and threatening, captured in a wide cinematic shot with sharp focus on the creature's intricate, scaled armor and mossy highlights.