Alastor had been walking briskly around the balcony, desperately looking around when he heard the voice. The song. The sound and feeling that seemed to creep around the din of the crowd and the ambiance of the casino. The feeling he could feel, he could notice, altering his mind. Where there was once concern and a feeling of imminent dread there was now promise, joy and imminent discovery - something new was just around the corner. 

He stopped and frowned for a moment to regain his bearings. This was quite possibly why he found it so important to take care of Chu - if she had been dragged back into the underworld, if she was raised as a "proper" demon and her ability grew while learning only to corrupt the results would be disastrous - at a charitable estimate. Entire masses of humans could be driven to greed, madness, corruption. Demons could grow, their numbers could explode into legion. The Demon Lord would surely take advantage of this boon to her plans of conquest. That had not been his primary motivation for taking Chu under his wing when he fled in the aftermath of his unsuccessful challenge but when he had discovered just what she could do - and as a young, child demon no less - it had become a major one. 

"Chu," he called out, turning to the banister which the song had originated from and his disapproval of her singing in his casino immediately overridden primarily by relief at her being safe and then more slowly by the urgency of the matter at hand. "There you are. Come down from there, something dangerous is happening."