Bill, Bloody Bill has no known offspring, and no known descendants.
The William Anderson who lived in Brown Co TX claimed to be the famed Bloody Bill in a 1924 local newspaper interview, but comparison studies of both William Anderson's families have shown this claim is not possible, as they were different men.
As you probably know, Bloody Bill was killed in Oct 1864, well documented, is buried in Pioneer Cemetery, Richmond MO. He had married Miss Bush Smith a few months previous in Grayson Co TX in March of that year, I have a copy of his marriage certificate, so if he produced a child that hasn't been identified, it was the only one possible. William C Anderson of Brown Co TX married his cousin Martha Anderson, and their first of 10 children was born in 1864.
Their names were similar, but not identical, as Bloody Bill's name was William T Anderson, and the Brown Co Anderson was named William Columbus Anderson.

I hope this is helpful, and gives you some new information to check out.
Fran Bolton