A menacing aquatic demon with a humanoid form and striking angular features emerges in the depths. Its shimmering blue skin contrasts with the water, and its furrowed brow adds to the intimidating aura. Sharp, jagged teeth are bared in a fierce snarl. The underwater backdrop, enhanced by Unreal Engine 4's capabilities, creates a vivid, immersive scene with rich textures and dynamic, cinematic lighting that casts eerie shadows around the creature. The demon's eyes, glinting with malice, are a focal point, drawing the viewer into this haunting underwater world.