Hollow Ones are often homes to pandaemonic hosts of spirits, fiends and remnant gods. They often become well practiced in coercing extra strengths from theses and even exploiting one versus another.
For the Hollow One mythic path from Mythic Paths of the Lost Spheres:
Draw the Chained (Mythic)
You utilize the void of your internal prison to draw power from creatures who have come to possess you.
Prerequisites: Brandish the Black mythic path ability, spellcasting, manifesting or binding level of 1 or higher.
Benefit: As a swift action, you may choose to to attempt to exhaust a possessing creatures power, spell, or spell-like ability by making an opposed Will save with it. If you succeed you may utilize the power of the exhausted spell-like power to revitalize your own powers. For each spell-like ability exhausted you may restore either: a spell-like ability of equal or lower level, a spell slot or retrieve a spent prepared spell of one level lower, recharge the cooldown of a binding of a spirit of one level lower than the ability, or regain power points equal to those required to manifest a power one level lower than the exhausted abilities effective level. If you fail the opposed Will save you yield control to your possessor for 1 round despite effects that might prevent this (such as a protection from evil spell). Each time per day you use this ability after the first your opposed Will save takes a cumulative -1 circumstance penalty.