His entire name is Damon Lee Fizzy. I don't think Damon ever said in his videos that Fizzy was his last name, but I'm pretty certain "Fizzy" accually is his last name.
It is Francesco. Damon's full name is Damon Francesco Salvatore.
DeeFizzy's real name is Damon Fizzy.
Les Damon's birth name is Lester Damon.
Damon Vracin's birth name is Damon A. Vracin.
Damon Runyon's birth name is Runyan, Alfred Damon.
Damon Stoudamire's birth name is Damon Lamon Stoudamire.
Damon Andres's birth name is Andres, Damon James.
Damon Berryhill's birth name is Damon Scott Berryhill.
Damon Curtis's birth name is Damon James Curtis.
Cathryn Damon's birth name is Cathryn Lee Damon.
Gabriel Damon's birth name is Gabriel Damon Lavezzi.
Johnny Damon's birth name is Johnny David Damon.