
Demonic Law and the Trading of Souls are this demon's specialities, Zahn was once a Low-Level demon that has over the years gained substantial power by offering demonic beings the souls of mortals in exchange for powers, selling the souls to the highest bidder.
Larry Henderson & Paige Matthews[]
A young businessman known as Larry Henderson was in financial ruin and came across the demon Zahn who offered him material wealth and success in exchange for his soul. Desperate to provide for his wife, Larry signed a Faustian Deal with Zahn stating that after a year of success and wealth, Zahn would collect his soul.
However, shortly before Zahn arrived to claim Larry's soul, Paige Matthews was hired by Larry and the temp agency as an assistant-secretary. The night that Zahn came to collect, Larry gave Paige an envelope of money, thanking her for her services; Paige was about the leave with the money but realized she couldn't accept it and when she went to return it to Larry, she saw Zahn claiming his soul.
Zahn took Larry's soul to his lair where he kept him imprisoned until he was ready to trade it. However, Paige soon tracked down Zahn, offering him her soul in exchange for letting Larry's soul move on to the Afterlife. Zahn agreed and drew up a contract for Paige to sign; Paige signed the contract and Zahn took her soul to his lair where he offered it to various demons eager to offer him power in exchange for the soul of a Charmed One.
Piper and Phoebe summoned Zahn to the Attic of Halliwell Manor in order to learn where Paige was but then he retreated back to his lair and proceeded to offer Paige's soul to demonic bidders. Piper and Phoebe tracked down Zahn's lair and before Paige's soul could be sold, Piper destroyed all of the contracts in Zahn's vault with her power of Molecular Combustion and the demon was vanquished. Paige's soul returned to her body.
The Faustian Deal[]
Keeping each contract an innocent signed in a vault in his lair, Zahn collected hundred upon hundreds of contracts containing agreements with mortals offering them success and wealth in exchange for their souls. The contract read thusly:

Faustian Deal
The undersigned hereby exchanges eternal rights to
his/her soul to the demon Zahn in exchange for
riches unimaginable. At the time of the undersign's
death, his/her soul will become property of Zahn to trade or
sell as he sees fit.
Furthermore, any party engaging in before mentioned
agreement will note that should Zahn perish
prematurely, souls in his possession will burn in
flames for all eternity. Subject to the provisions set forth
above, the agreement is legally binding and will begin
immediately upon signature.
____________________
Mortal
____________________
Zahn
The Book of Shadows[]
The sisters located an entry in the Book of Shadows describing Zahn However, the entry did not contain information regarding Zahn's trading of Soul iin exchange for power. Although the Book stated that Zahn was Low-Level, in actuality he became extremely strong due to all the powers he acquired via trading souls. The entry read:

Zahn
A lower level
demon
and soul trader
who specializes
in demonic
contracts and
demonic law.