The living embodiment of sound, music and, well... insanity.
Sonitus rarely, if ever, takes a a physical or at least visible form and is generally thought not to have one. The demon, considered female by many including herself, instead can be heard as a great number of things. Normally it is music of kinds varying upon her mood or simply hearing her footsteps, her breath or sometimes feeling her touch and its volume seems to indicate the size of her form though this is an illusion. Her voice is beautiful but hysterical and often distorted, her insane laughter creeping into your mind. Her image only seems to appear when certain songs are played, when it does its varies according to whom is observing it but it is almost always feminine and constantly flickering like a damaged video.
Sonitus is, frankly and quite honestly, mad with complete focus on creating 'art' and little regard for the implications of her work. She is playful and frivolous most always, adoring playing cosmic pranks on others and otherwise tricking mortals. Her eccentricities are extensive, a mind very complex and intelligent but somehow broken, unstable leading many to believe there was a fault in her creation. These people may be right, her thoughts increasingly disorganized and confused, seeing or hearing things that are not there which can then, due to her power, become real with unfortunate circumstances. Her mental state is infectious, prolonged exposure to her presence has been know to give even the most ordered deities to become a little irrational. That being said she is probably the least malevolent of the demons, not purposely harming others. Music is deeply tied in with her state of being, songs having the ability to change her nature dramatically for a short time if they are of a high enough quality.
She harnesses Demonic Energy and at times it seems sound and music itself.
When Sonitus was being created, demonic energies pouring into her form, a single note rang through the mold by chance and into the being. The vibrations cracked her mind and left of physical and visible aspects damaged, too late to undo the effects and was allowed by Sandron to continue existing out of Sandron's curiousity as to its effects. The result was thing very strange and insane demon, intent on using the Oververse as a canvas for her madness.