The Berserker staff is an Asgardian staff embedded with magic. The staff was split into three parts and hid on Earth by an Asgardian soldier known as Elliot Randolph. The Berserker staff enhances the individual, but makes them more aggressive.
In 2013, Norse Paganists Jakob Nystrom and Petra Larsen found part of the staff in Oslo, Norway. They then tracked down Randolph in Spain and found the final piece at a monastery in Ireland. S.H.I.E.L.D. agents Grant Ward and Melinda May managed to defeat Nystrom and Larsen, and took the staff.