Power Absorption is the ability a Caster has. It is the ability to absorb the powers of other Casters and presumably Incubuses by touching them without actually removing them. Unlike Empaths and Evos, the powers they absorb are permanent. It is unknown if any other Casters have this power.
John Breed, the Caster-Incubus hybrid, is the only known Caster that possesses this power. He calls all the powers he collects his "collection". He absorbed the Ridley's Siren power and Lena's Natural/Cataclyst powers. He has also absorbed powers from Macon, an unknown Thaumaturge, a Dark Cypher and Angelus.