Robert Grimaldi is a student at Yale and a friend to Logan. He and Rory first meet at a poker party that is an unoffical first date for Logan and Rory.
Rory and Robert go to Finn's costume party together. This makes Logan very mad, even though he and Rory are not in an exclusive relationship.
Robert is also part of the Life and Death Brigade.
Grimaldi is not Robert's real last name.