Hazel is Matthew and Kai's Adoptive Daughter, she's always confused for Hilda, which makes sense.

Hazel is 20 years old (Matthew and Kai adopted her when she was 17)

Hazel really loves her Partner, Faith (Link and Amie's Adoptive Daughter), since both of them have been together for a long time, Matthew and Kai adopted Hazel, and Link and Amie adopted Faith, so both girls can be partners.

Hazel really loves Cucumber Sandwiches.

Hazel and Matthew do not have any biological origin, Hazel was given Matthew's Genes, and Faith got Kai's Genes, therefor both of them can't die.

(Faith is Frida's new name by the way)

Honestly, Hazel is a cuter name for this Hilda variant, thats why i chose it.

Hazel is not a Hilda AU, in fact, Hazel is completly unrelated with Hilda at all.