Frida Goth

Frida Goth is a member of the Goth Family (featured in both The Sims and The Sims 2. She is deceased long before the start of the game in The Sims 2, yet her relatives reside in Pleasantview and are ready to be played.

According to the Goth Family tree, Frida is the sister of Gunther Goth, father of Mortimer Goth. This would make Frida the aunt of Mortimer, and thus the great aunt of  Mortimer's two children,  Cassandra and  Alexander. Frida apparently never married, and never had any children.