Ennead Vi.2 presents itself as Plotinus' official account of the structure of the second Hypostasis, i.e. Intellect (νοῦς) or Being, what corresponds in his metaphysical universe to Plato's realm of Ideas or Forms. Having refuted the Peripatetic and Stoic theories in VI.1, he turns to developing his own view of Being, which he intends to be in agreement with Plato's. Indeed, the account of the 'genera of being' that he give in VI.2 is closely modeled on Plato's discussion of the so-called 'greatest kinds' or megista gene in the Sophist.
Strange, Steven K., "Plotinus on the Articulation of Being" (1989). The Society for Ancient Greek Philosophy Newsletter. 155.