Phalse was a being with beholder-like characteristics, except that his tentacles ended in mouths. Other beholders found this disgusting.
Phalse was one of the six involved in creating the human construct Alias. His symbol was a blue-upon-blue circle, presumably representing a beholder's central eye.
He pretended to be a servant of a greater being of the Abyss, so he would have greater freedom to act. He disguised himself as a halfling, on a construct body.
Phalse was slain by Alias, who impaled him with the sword of Dragonbait, Hill Cleaver, and used it to throw him upwards from the top of the Citadel of White Exile into the Positive Energy Plane, where for all intents and purposes he became an exploding star.