The Fritz family was the original royal family of Eldia that used the power of the Founding Titan to rule over their lands. After the Great Titan War, the family split in two, with some staying on the mainland continent that was conquered by Marley, and the others entering the Walls that Karl Fritz had built. The branch that went inside the Walls disguised themselves as a minor noble family known as the Reiss family.
By 824, Dina Fritz was the last descendant of the royal family still living in the mainland. Dina then joined a rebellious organization but was caught and turned into a Pure Titan. Although the royal bloodline lives on with the Reiss family, the Fritz name is effectively extinct.
History: Around 2000 years ago, Ymir's village was attacked and enslaved by the Eldians, who then cut out their tongues. One day after a pig was released, the tribe's ruler called all of the slaves and asked for the culprit. The slaves all began to point at Ymir, who was then "freed" only to be hunted by dogs and men.
Story: Thirteen years after wandering as a Titan, Dina is among the many Titans that invade Shiganshina District in the year 845 when the Colossal Titan and Armored Titan breach the gates of Wall Maria. She wanders throughout the district until coming to the home of the Jaeger family, where Carla Jaeger, Grisha's second wife, lays helpless beneath the rubble of their ruined home as her children attempt to free her. As a Garrison soldier carries the children to safety, Dina pulls Carla out of the rubble, eating her as any normal Titan would.
Trivia: As seen with Zeke, if a member of the Fritz family were to inherit any of the other Nine Titans, outside of the Founding Titan, they would have gained powers similar to the Founding. This would have primarily allowed them to create new Titans through a Subject of Ymir ingesting their spinal fluid, and the inheritor then screaming. "Fritz" is a German diminutive of the German Friedrich and means "peaceful ruler".
Source: Fritz family (Anime), available under CC BY-SA 3.0.