Noah Mercer was the father of Lena Leger and the grandfather of Aspen Leger.
He is only known because of the Leger family tree.
The Mercer family were restaurant owners. They were friends with the Gillespi family, who owned a restaurant, too. The Mercer son, Noah, fell in love with the Gillespi daughter, Orin. They married and had four daughters. Orin and Noah saved money so that the oldest daughter, Lena, could buy her way back to the Three status the family should have, and help the rest of her siblings.
Lena took the money to marry a server in their restaurant, Elec Leger. After their marriage they told them and Lena was unceremoniously kicked out of her family, left with no one but Elec.