Asmodeus

Asmodeus's true form was that of a wingless scaled serpent hundreds of miles long. His form's sheer size made it impossible for him to meet and enter into conversations with others. Therefore, he created humanoid-looking avatars. The location of his body was kept secret from everyone, including other Devils and everyone who learnt of the truth about his body was killed within a day.
Asmodeus never showed himself except through avatars or project image, both in humanoid forms. Asmodeus's avatars looked like a slim, charismatic, red-skinned humanoid over 13 feet (4 meters) tall, with horns on his head and glowing red eyes. Overall, he had charismatic and beautiful looks that captivated people. He always had a perfectly trimmed beard and wore very expensive red and black clothing, which were valuable enough to cover the annual national spending of any nation. However, underneath these expensive garments, the body was wracked with bleeding injuries. While he was in pain, he managed to give the impression of someone unconcerned with the pain the injuries caused him. He could manifest ten avatars at once if needed, allowing him to station one on each layer of Hell if he needed to, with a tenth leftover for managing extraplanar duties.