An aquatic demon with a sleek, humanoid form and sharp, angular features stands menacingly in the dim underwater world. Its bluish skin shimmers as it catches flickers of light, highlighting the deep furrows of its brow. Razor-sharp teeth are bared in an intimidating snarl, the open mouth suggesting an unearthly roar. The ambient murkiness of the underwater background enhances the scene's mysterious allure. This 3D representation, crafted in Unreal Engine 4, showcases dramatic cinematic lighting that accentuates the creature’s otherworldly presence.