Grandpa Chase

Grandpa Chase is the father of Randolph, Natalie and Frederick Chase, husband of Grandma Chase and grandfather of Annabeth, Aubrey, Bobby, Matthew and Magnus Chase.

History
Grandpa Chase lived in Boston and at one point married a woman and fathered two son and a daughter. He lived in a six floor Boston brownstone mansion which he gifted to his oldest son. He and his wife died before meeting their grand children.

The Sword of Summer
Magnus Mentioned his grandfather when entering his family's house.

The Ship of the Dead
Magnus finds a picture of him and his wife in the mansion's library.