  The first derivation from the One is Intellect.  Intellect is the locus of the full array of Platonic Forms, those eternal and immutable entities that account for or explain the possibility of intelligible predication.  Plotinus assumes that without such Forms, there would be no non-arbitrary justification for saying that anything had one property rather than another.  Whatever properties things have, they have owing to there being Forms whose instances these properties are. But that still leaves us with the very good question of why an eternal and immutable Intellect is necessarily postulated along with these Forms.