Spawn of Cthulu
So far, we only know of one spawn of Cthulu, and it was a she.
She would go on to form a crime fighting duo with Mercury, the daughter of Benjamin Blackburn. They together would be responsible for the capture of many infamous criminals of the Victorian era.
She was found on the shore of London near the mouth of the river Thames. She like her friend Mercury seemed to have been abandoned, only she was found washed up on the beach. As far as we know, the monster Cthulu had been known to go abroad possessing unaware humans and seeding himself in an attempt to spread wanton destruction. But in this case, one of his spawn rebelled, being the exact opposite to what was intended for her. She would of her own choice became a steam punk crime fighter, joining forces with the daughter of a wizard.