Dual Catalysts
Through many Erdtree rebirths, the Warlocks have mastered both schools of magic.
About
Dual Catalysts are a new weapon type introduced in Elden Ring: Dark Moon.
As opposed to regular catalysts like Staves and Seals, Dual Catalysts grant the ability to cast both Incantations and Sorceries. This usually comes at the detriment of a lack of specific power increase like how the Meteorite Staff specializes in Meteor Sorceries.
Scepter of The All-Knowing
In Dark Moon, Gideon Ofnir's Scepter has been changed from a hammer to a Dual Catalyst. It still drops after defeating him.
Talisman of Beasts
The Talisman of Beasts returns from Demon's Souls where it was also a Dual Catalyst. Begin as a Warlock or purchase it from the Ranni Puppet at Roundtable Hold.