WARNING: Potential Spoilers Below!

Name: Eysteinn

Nickname: Glumra ("Noisy Clatterer")

Cultural Background: Northmenn (made his home in Northmenn-settled Urkneyjar Islands)

Born: Unknown

Parents: Unknown

Noble House: Uncertain

Spouse: Asa Ragnvaldardottir (Asa Eidhsvardhkona, Asa Oathkeeper)

The husband of Asa Oathkeeper (they met and married in The Saga of Asa Oathkeeper). He has very light blonde hair, eyes that are almost violet, and often wears a much-patched chainmail byrnie (inherited from his father) that rattles as he walks, hence his by-name Glumra, which means something like "Noisy Clatterer." 

Appears In: The Saga of Asa Oathkeeper and Asa Oathkeeper Among the Giants

Source: Loosely based on a historical Eysteinn Glumra, who some sources say married an Asa, but mostly the creation of Colin Anders Brodd, conflating several historical figures with the fantasy creation.