Sphinxes are Others of Balance, driven to preserve it no matter what. They are sensitive to things that alter or damage the balance, with demons and their taint being unpleasant to painful to be around and those from the choir of madness being enough to completely cripple them. Their race was artificially created and served primarily as sentinels.
When born, the strongest of a litter will eat the weaker siblings, and they are genetically incapable of caring if someone dies so long as the death is in the right place and time. However, they can learn from experience and can emulate human emotions. Likewise, they can suppress the instinctive drive to attack the ignorant, but telling a lie to a sphinx allows them to exercise their right to atone the balance, which often ends in death.
Because one of their duties is to remember things, even if connections are cut or erased from existence, they can hold onto fragments or more.