Physical increases do not effect muscle mass, allowing the wearer to maintain a smaller body, but have the strength of a body-builder. Many wearers opt for a runner's physique.
When a Soul Mask is first worn, it forms a link with the wearer's Soul. This can cause temporary insanity, repition of words and a permanent inability to write or type correctly. Once it is bonded with the wearer, it will not work for anyone else.
If the wearer fully accepts the Soul Mask and its power, the design on the mask prints onto the wearer's face and all the power is transferred with it. The mask itself becomes a useless husk, but retains its design. Many wearers continue to use the mask, despite having all of its powers contained within them.
After a significant amount of time has past (more than 50 years of being Imprinted) and the wearer has performed a specific Theurgic Ritual, called the Ritual of Bonding, the power of the wearer can be amplified by the power of the Imprinted Soul Mask. While increasing the wearer's power, it also allows a second Soul Mask to bond with the wearer, creating even higher power. The markings of the mask move from the wearer's face to their eyes.
Ownership of a Soul Mask can willingly be given up and given to another person so long as the wearer has not been Imprinted. Imprinting is permanent and cannot be undone.